Police want John Campbell and other Campbell Live journalists to reveal the identity of the man who confessed to the theft of the Waiouru Army Museum war medals on the TV show.
Naming the supposed thief could provide the "king hit" for an otherwise circumstantial police case against the two men accused of the burglary in December 2007, Crown prosecutor Lance Rowe told the High Court at Auckland yesterday.
Justice Tony Randerson has reserved his decision on the police application for a court order to compel Campbell, Carol Hirschfeld, Ingrid Leary, Hannah Story and Zoe Duffy to give evidence in court.
Justice Randerson continued name suppression for the two men, aged 37 and 39, accused of taking the 96 medals, including nine Victoria Crosses.
The Chief High Court Judge also suppressed the facts of the Crown case heard in court yesterday and the publication of a confidentiality agreement between the police and criminal barrister Chris Comeskey.
A $300,000 reward was offered for the medals, which were safely returned after Mr Comeskey brokered a deal with the thieves in February last year.
Shortly afterwards, Campbell Live screened an interview with a man called "Robert", who said he had taken part in the burglary at the museum.
Viewers saw a man wearing a hood with his face in shadow being interviewed by Campbell. The audience was told an actor's voice had been used to protect the man's identity.
Campbell and TV3 later admitted they made a mistake by not telling viewers that the interview was a re-enactment which used an actor.
The police application seeks a court order for the television journalists to reveal the identity of "Robert" and answer any questions about the interview.
Campbell Live staff promised "Robert" they would keep his identity secret in order to secure the interview. Media are protected by privilege from revealing confidential informants but Mr Rowe said the privilege was "not set in stone".
The right of a journalist to protect a source had to be balanced against the public interest, which Mr Rowe said normally favoured the news media.
In this case, the prosecutor said public interest outweighed the journalistic privilege and all the relevant facts should be put before a jury.
"What the public really want to know was who [Robert] was. That's what is really in the public interest."
Julian Miles, QC, acting on behalf of MediaWorks TV, opposed the police application and said journalistic privilege could only be over-ridden in "exceptional circumstances".
He feared that forcing Campbell to expose "Robert" would have a "chilling effect" on anonymous sources who help the media as a public watchdog.
But Mr Rowe questioned whether the case of the Campbell Live interview, a confession to a serious crime, could be compared to a whistleblower coming forward to expose corruption.
Police want the Campbell Live team to identify "Robert" at a depositions hearing in the Wanganui District Court in October, or any later trial.
Mr Rowe said he would file a similar application for the court to compel Mr Comeskey to give evidence. Mr Comeskey has said he would defy any order and risk jail time for being in contempt of court.
The depositions hearing has tentatively been set down for three weeks beginning on October 26.