Police waited too long to enter the Lindt cafe stronghold in their attempt to rescue hostages from the gunman Man Haron Monis, NSW Coroner Michael Barnes said in a finding endorsed by Police Commissioner Mick Fuller.

Commanders relied on "flawed advice" from negotiators and a police psychiatrist that underplayed the risk Monis posed and overestimated their chances of a peaceful resolution, the coroner found.

Storming the cafe in a surprise assault to end the terrorist attack would have been safer. But having hung back, preparing for an emergency, police should have then pounced when Monis first fired his shotgun at escaping hostages.

These were among the findings in a 600-page report into the handling of the siege, handed down on Wednesday morning.

But Mr Barnes said he could not "stress too heavily" that the deaths of hostages Katrina Dawson and Tori Johnson were not the fault of police.

"All of the blame for those rests on the shoulders of Man Monis. He created the intensely dangerous situation. He maliciously executed Tori Johnson. He barricaded himself into a corner of the cafe and his actions forced police to enter the cafe in circumstances where the risk of hostages being wounded or killed was very high."

The coroner commended the "inspiring" bravery of the officers who entered the cafe, believing Monis could have detonated an improvised explosive device. He emphasised it was not his role to assign blame but to make findings of fact and recommendations.

Among his key recommendations were:

• an overhaul of police negotiator training
• the creation of a specialist cadre of counter-terrorism negotiators
• a reconsideration of the entrenched philosophy of "contain and negotiate"
• a clarification of snipers' legal power to shoot
• a review of the the threshold for calling out the Australian Defence Force in domestic terrorism situations
• the sharing of criminal bail histories among all Australian jurisdictions
• more collaboration between NSW Health and NSW Police to identify "fixated" offenders
• an overhaul of the ASIO triage system for tip-offs

Mr Barnes found police commanders were wrong not to have approved or considered an earlier intervention in a so-called "deliberate action" plan.

A decision "to enter the stronghold at a time of their choosing would have increased the chance of surprising the hostage taker and thus reducing the risk to the hostages".

This view has been echoed by Mr Fuller in an interview released by the ABC's Four Corners, in which he blamed "poor advice".

"In hindsight, as with everything, we know we should have gone in earlier," he said. "Clearly a deliberate action is a much more professional action and a lower risk."

Monis, an Iranian refugee who assumed "wildly different guises" in Australia, was not psychotic but may have suffered from a personality disorder when he took the eight cafe staff members and 10 customers hostage on December 15, 2014, the coroner found.

"The terror they endured could fairly be described as torture. Monis oscillated between feigning regard for their welfare and threatening to blow them apart with shotgun blasts or a bomb.

"They had entered a familiar environment only to find it transformed into a prison run by a vicious maniac. Public recognition of their suffering and the extraordinary courage some demonstrated is warranted."

Throughout the day, senior police said negotiators were working with Monis. But the coroner found negotiators made no progress and did not undertake a "structural assessment" of their prospects. A consultant police psychiatrist overstepped his role, providing "erroneous" advice that went beyond his expertise.

"Police commanders underestimated the threat Monis posed," the coroner found.

The negotiators and the consultant psychiatrist had told them "negotiations were progressing, that the stronghold was calm, that Monis' behaviour was not consistent with Islamic State methodology - he was merely "grandstanding", and, towards the end of the night, [Monis] was beginning to "settle".

The coroner made no adverse findings against Deputy Police Commissioner Catherine Burn and former commissioner Andrew Scipione, although he found Mr Scipione at one point strayed beyond his remit into operational matters. The two police shooters on the night, Officers A and B, did not fire excessively nor indiscriminately.

But Mr Barnes concluded that emergency action ought to have been initiated when Monis first fired his shotgun at a group of escaping hostages at 2.03am.

"The 10 minutes that elapsed without decisive action by police was too long."

Mr Johnson was executed at 2.13am while police were still deciding whether to enter.

Ms Dawson's parents, Alexander and Jane, and her brothers, Angus and Sandy, were in court for the findings. So, too, was Mr Johnson's partner, Thomas Zinn, and his parents, Ken Johnson and Rosie Connellan.

Lindt hostages Louisa Hope, her mother Robin, and Paolo Vassallo were also present.

Submissions from the families will be made available on Monday but the families have publicly condemned police for not entering the cafe earlier.

Mr Zinn said during the inquest "one shocking discovery followed the next".

"Soon it became apparent that we were not simply fighting for the truth of the circumstances of Tori and Katrina's deaths," he said.

"Rather, we were confronted with systematic failures of various authorities who, at times, were confused, ill-informed, unprepared and under resourced to deal with Monis."