Paid interviews with Sydney siege hostages should be prevented from going to air because they risk tainting future evidence and weakening the coronial process, former state coroner John Abernethy says.

Former Director of Public Prosecutions Nicholas Cowdery also fears hostages involved in exclusive cash-for-comment deals may give colourful, definitive accounts to satisfy a television audience, then feel compelled to repeat the same accounts in court, even if their views have shifted.

The NSW Coroner's Court says it is monitoring the effect of media coverage on the inquest. Channel Nine says it is working with police to ensure its broadcast is accurate and Channel Seven says the hostage accounts are "intensely personal stories which go beyond the witness box".

Siege survivor Marcia Mikhael has reportedly been signed by Channel Seven for $400,000, while John O'Brien will be paid $100,000. Nine's 60 Minutes program is rumoured to have signed four Lindt cafe workers – Fiona Ma, Harriette Denny, Joel Herat and Jarrod Morton Hoffman – for a combined $1 million. However those figures are disputed.

The coronial inquest into the siege begins on January 29, however it may be some time before witnesses are called to appear.

Mr Abernethy, the coroner from 2000 to 2007, said if the hostages' interviews air before they appear in court, it risks "tainting the actual eyewitness evidence".

"[The hostages] may embellish [their accounts] before the coroner, they may feel compelled to say what they said on television and it just loosens the whole thing. It runs a real risk that it's not going to be the best evidence," he said.

Mr Abernethy said if he were the coroner, "I'd be discussing with my team the possibility of stopping those interviews" through Supreme Court action.

Mr Cowdery QC said the interviews were "inappropriate" and may undermine the integrity of the coronial process.

The television journalists interviewing the hostages would be "looking for drama … looking for colour" and may influence the way the stories are told, he said.

"There's a risk that [the hostages] will fill in gaps in their own direct knowledge so as to please the person who is paying for their account," Mr Cowdery said.

The hostages were also being "paid to commit themselves to a particular version" and "would feel diffident about changing their stories in any respects because they might be criticised for being mistaken or … making things up," he said.

Bret Walker, SC, a leading NSW barrister, agreed that hostages giving evidence under oath may be unwilling to diverge from their earlier televised accounts, which may have been "less than deadpan accurate". He said this was "unlikely to enhance the coronial investigation".

But Mr Walker stopped short of calling for a ban on media interviews ahead of coronial proceedings "because of the effect it has on freedom of the press".

A spokeswoman for the NSW Coroner's Court said it was working with critical incident investigators to monitor media coverage "with a view to assessing whether the publication of interviews is likely to undermine the efficacy of the inquest".

"There are no rules in place regarding whether witnesses can give interviews prior to an inquest," she said.

A Nine spokeswoman said 60 Minutes has been working closely with police "to ensure the factual integrity of the story" and the hostages were giving interviews "after finalising their police statements, and with the knowledge of police".

A Channel Seven spokeswoman said it would never wish to "interfere with the conduct of a proper inquiry".

"But these are intensely personal stories which go beyond the witness box and it's a bit beyond the pale to accuse people of colouring accounts of what would have been an horrific and harrowing ordeal," she said.

Victims of crime advocate Howard Brown this week defended the hostages' right to sell their stories, after former Victorian Premier Jeff Kennett described the payments as "plain grubby". But Mr Brown said hostages might find themselves in an "awkward position" if they "said one thing in an interview yet said something else in evidence".