The psychiatrist found to have given flawed advice to police negotiators during the Lindt cafe siege described any criticism against him as “grossly unfair”.

The New South Wales coroner and families of victims Tori Johnson and Katrina Dawson were scathing of the actions of a consultant psychiatrist, who cannot be named, during the police standoff with terrorist Man Monis in 2014.

The psychiatrist was found to have gone beyond his area of expertise by providing advice on Islamic State, negotiation strategy and tactics, and giving erroneous and unrealistic assessments of what was happening inside the Lindt cafe.

He told police Monis was a grandstander, that his actions did not fit with Isis methodology, and that the situation was calming down inside the cafe in the early hours of the morning, despite evidence suggesting otherwise.

His judgments were used by police to help assess the risk posed by Monis and decide whether and when to storm the cafe. The coroner found police did not properly understand the limits of the psychiatrist’s expertise.

The Dawson family were damning of the psychiatrist. Their submission to the inquest, released on Monday, said he should never again “be in a position to influence police decision-making”.

The family argued that having a genuine counter-terrorism expert to provide advice would have “quickly corrected many of the erroneous assumptions on which the psychiatrist was relying”.

But the psychiatrist’s own submission, also released on Monday, described any criticism of his actions as “grossly unfair”, arguing the court had not called any expert with relevant knowledge of his role to assess his performance.

The submission said he was simply providing an “unbiased and unabashed opinion on human behaviour in a high-pressure and tense environment”.

“Critically, [the psychiatrist], a consultant, held no rank, gave no orders, and we submit, did nothing less than what was required of a psychiatrist,” the submission said.

The NSW police similarly defended the psychiatrist. It said his advice was considered appropriately and filtered by the siege commanders and negotiators.

“The NSWPF makes no criticism of [name removed],” it said in its submission.

“He understood his role and his presence provided a helpful clinical perspective for the command and the negotiation cell. The negotiation cell transcript demonstrates that he was used as a ‘sounding board’ for negotiators.”

Coroner Michael Barnes was critical of the length of time police waited to storm the stronghold.

On Monday night, the ABC’s Four Corners reported the Johnson family wanted NSW police to review the positions of the two most senior commanders involved in the siege, assistant commissioner Mark Jenkins, and the forward commander, whose name was suppressed.

“Under the benefit of hindsight, throughout the inquest, they have proven that they ... that they didn’t understand the consequences of their actions,” Johnson’s partner, Thomas Zinn, told the ABC.

The Dawson family was also angry at police’s failure to learn from their mistakes.

Angus Dawson, the brother of Katrina, praised frontline police for their bravery but said the mistakes of leadership had let people down.

“My image of the siege will always be of those police in full tactical gear, surrounding the cafe, willing to put their lives on the line to go in, the hostages inside, Tori and Katrina being so brave in all the things that they did during the day ... but then this other image of these leaders of the police force making all these mistakes and letting everyone down,” he told the ABC.