A joint government inquiry into the Sydney siege may contradict the findings of an independent coronial inquest, confusing the public about the truth behind the tragedy, former NSW coroner John Abernethy says.
Another former coroner, Mary Jerram, said the coronial inquiry would be untainted by personal interests and should be considered the final word on how the hostage crisis unfolded.
Legal experts last month raised concerns that the joint NSW-Commonwealth probe lacks transparency and independence – claims Premier Mike Baird deflected by pointing to the independent coronial inquiry.
However, Mr Abernethy said the tandem inquiries were worrisome and, if they produce differing conclusions, may "undermine each other".
"It will be disturbing and the public will be confused and critical," Mr Abernethy said.
The government inquiry threatened to usurp the role of the coroner who was well-qualified and "trained to be independent, trained to judge and evaluate evidence", he said.
Mr Abernethy, the NSW coroner from 2000 to 2007, said coroners had the power to investigate national security and other federal matters.
NSW Police have been forced to defend the chain of command enacted during the Martin Place siege amid questions over whether state protocols for terror incidents were properly followed. There have also been reports that hostage Katrina Dawson was struck by a police bullet, possibly a ricochet.
Ms Jerram, the coroner from 2007 to 2013, said should the inquiries produce different findings, the coroner's word should be considered final, because the process was "independent and judicial".
"Being judicial means you have sworn to be independent, not show affection or ill-will and you haven't got anything personal to yourself, which you are defending or attacking," she said.
Ms Jerram echoed Mr Abernethy's concern, reported by Fairfax Media on Thursday, that paid TV interviews with siege hostages risk tainting evidence later brought before the coroner. Mr Abernethy said the broadcast should be banned.
Ms Jerram said if she was coroner, she would ask to watch the interviews before they aired, to decide if an injunction should be sought.
A spokeswoman for the NSW Coroner's Court said it was not concerned about the report of the joint government review. The coroner and those assisting him have been working closely with the government review "to avoid any confusion or any unnecessary duplication", she said.
Mr Abbott said on Tuesday the the joint government review would likely deliver its findings by the first week of February.
Mr Abbott, Mr Baird and NSW Attorney-General Brad Hazzard declined to answer questions on Thursday.
Channels Nine and Seven have both reportedly secured paid interviews with hostages. Nine says it is working with police to ensure its broadcast is accurate and Seven says it would never wish to interfere with an official inquiry.
with Heath Aston
