New South Wales coroner Michael Barnes' unflinching examination of the December 2014 Lindt cafe siege, handed down on Wednesday, runs to an epic 500 pages and will be combed over by law enforcement and intelligence agencies for weeks to come.

Undoubtedly it will spark a major rethink around the country of how police respond to future terrorism events.

By an accident of timing, the report landed a day after the appalling carnage in the northern British city of Manchester.

Barnes described the Lindt siege in his report as a "a stark reminder of the arbitrariness of life", writing in a poignant aside that "for every customer stuck in the cafe when the siege began, there was one who had departed just early enough, or arrived just late enough, to avoid being caught up in Monis' terror".

In Manchester, too, that same terrible lottery of chance and fate played out .

Australians are fortunate not to have faced an attack on that scale. Even so, the Lindt siege was an "unprecedented event" in this country, NSW police chief Mick Fuller pointed out this week.

Barnes quoted an international expert assessing that it would have challenged "any police force in the world".

That said, police had had years to prepare for the growing complexity of terrorism challenges unleashed by the rise of Islamic State and its murderous adherents.

So it was all the more sobering to see the sheer range of deficiencies identified by Barnes in the police response to the siege, though some were of greater magnitude and consequence than others.

These ran from weaknesses in negotiating tactics, to equipment and training deficiencies, poor intelligence co-ordination, critical lapses of communication at key points in the final stages of the siege, lack of clarity about the "triggers" for storming the cafe, failure to grasp the lethal threat that gunman Man Haron Monis represented, failure of police commanders to push for more creative thinking when their "contain and negotiate" strategy was clearly stalling, and the bungled way in which the families of the two hostages who died in the siege - cafe manager Tori Johnson and barrister Katrina Dawson - were given the news of their loved one's deaths.

It wasn't until nearly three hours after police stormed the cafe, for instance, that the Johnson and Dawson families learnt of Tori and Katrina's fate, a delay the coroner described as "unjustified".

Criticism extended beyond the police. Monis should have been behind bars after being charged with a string of offences ranging from sexual assault to being an accessory to murder. Instead he was out on bail, earning a rebuke from Barnes for the Office of the Director of Public Prosecutions.

Similarly, ASIO had had Monis on its radar for years, but did not flag him as a concern, despite his sparking 18 calls to the National Security Hotline in the days before the siege. A consultant psychiatrist was allowed to overly influence the course of negotiations, his assurances that Monis was "grandstanding" helping to lull senior police into a state of complacency about the progress of the siege.

The Australian Defence Force and the Australian Federal Police had a marginal role on the night but could have done more, Barnes suggested.

Yet some of the fault for that must lie at the feet of NSW police and political leaders. Then Prime Minister Tony Abbott's chief of staff, Peta Credlin, revealed this week that Abbott had offered to provide then premier Mike Baird with military personnel and ballistics experts early on in the course of the siege.

"The Premier said they didn't need it at that stage and thanked the Prime Minister for the offer," Credlin said pointedly.

One of the clearest themes to emerge from Barnes' 45 recommendations is the need for police to rethink their deeply entrenched "contain and negotiate" mindset when confronted with terrorist actors. In essence, this boils down to no longer waiting it out but acting early and pre-emptively. The Lindt siege dragged on for 17 hours without negotiators making any progress. Only the execution of Johnson by Monis forced police into action.

Fuller accepted on Wednesday that police had waited too long, and would act more swiftly under similar circumstances in future. "The terrorism threat is evolving and we need to evolve with it," he said. But he cautioned that earlier entry would not necessarily have guaranteed a better outcome.

"World standards would say early engagement was necessary ... it does not [necessarily] mean less lives lost, it may mean different lives."

Police are likely to beef up their armed presence on the streets. Just before his retirement in April, former police commissioner Andrew Scipione predicted Sydneysiders would soon see police officers carrying long arms, and Fuller is moving forward with that proposal. The force is currently trialling different weapons before picking a supplier, aiming to roll them out first across the Public Order and Riot Squad.

Former deputy police commissioner Nick Kaldas, now working abroad in a senior policing role with the United Nations, also flagged the need recently for more overt shows of police firepower. He told a Safeguarding Australia summit in Canberra in early May that there needed to be a "harsher, deterring" presence for police and security offices at places of mass gatherings, with tactical teams in "full kit" patrolling on foot.

That flows into a growing debate about whether a more explicit right to "shoot to kill" should be invested in police.

The coroner found that while snipers on the night had no opportunity for a clear shot at Monis, they'd felt hamstrung in any case by being unsure of their legal right to shoot before he'd physically harmed any of the 18 hostages.

"It may be that the special powers available to police responding to terrorist incidents should include a more clearly defined right to use force," Barnes suggested. Abbott has since come out in enthusiastic support of "shoot to kill" where police reasonably suspect they are dealing with a terrorist event, and NSW Police Minister Troy Grant, a former officer, is looking favourably at Barnes' recommendation.

But there has been a lukewarm response in Canberra, with Counter-Terrorism and Justice Minister Michael Keenan saying police already have "every power necessary to respond with required force to remove a terrorism threat".

Civil liberties groups, too, are urging caution. On Wednesday, Fuller played his cards close to his chest, saying issues around "taking a life or saving a life" were not to be treated lightly, but he will almost certainly be taking some action on Barnes' recommendation.

A review of the role of the Australian Defence Force in future terrorism crises has also gained fresh momentum following Barnes' report.

The current threshold for ADF intervention is set high. State police and political leaders have to decide an unfolding crisis is beyond their capabilities before the ADF is invited in. In the case of Lindt, NSW authorities seemed highly resistant to that option. Barnes has questioned whether "given the rise of global terrorism and Islamic jihadist movements ... the traditional roles of domestic police forces and the ADF in Australia ought to be reconsidered".

That is already happening, though what's most likely to emerge is slashing of red tape to enable easier sharing of ADF resources with the states rather than an overriding power for federal agencies to step in. Federal Attorney-General George Brandis said this week that "it is important, I think, that when there is a major terrorist episode of the kind that we've lately seen in the United Kingdom, that all of the capabilities that the country has that may be useful to deal with that terrorist event are at the disposal of the operational commander".

On the whole, Barnes' report has met with a strongly positive reception, though the bereaved Dawson and Johnson families are yet to give a comprehensive response. There is much for them to consider.

Despite some speculation in advance of the reports's release that former police chief Scipione and deputy Cath Burn would attract some criticism, the coroner has made no adverse findings against them.

Neither officer had, or should have had, a role in directing operations on the night of the siege under existing NSW counter terrorism protocols, Barnes heard.

Indeed the lawyer representing the senior officers at the inquest told the coroner that the pair "did not give any orders, directions or provide any guidance or advice in respect of the conduct of the siege on the day".

But some believe their role on the night was too hands off. "They did not have to be designing the details of the operation, but in my view, they had a responsibility to ask if the strategy was working, and if not, what the alternate strategy was" argues one former senior police commander.

It would be surprising if Mick Fuller hasn't taken this lesson on board, too.