Both Labour and National tongues are tied over a potentially explosive ruling due out today from the Electoral Commission.
Newstalk ZB's obtained a copy of the commission's decision regarding a Labour Party complaint over a show the Prime Minister conducted on RadioLive during last year's election period.
The commission's found the broadcast was an election programme and a breach of the Broadcasting Act.
Newstalk ZB understands both Labour and National have been given advance copies of the decision but are bound by a confidentiality agreement not to talk about it until its officially released at five this afternoon.
A win for Labour of sorts after the Electoral Commission ruled an hour long radio show hosted by the Prime Minister broke the law.
Labour complained at the time that the show was unfair and illegal, as then leader Phil Goff was never offered the same opportunity.
Deputy leader Grant Robertson says it gave the National leader an unfettered hour of radio in which he could align himself with people he called friends - and the show did exactly what the broadcaster had been warned not to do.
Police now have to decide whether to prosecute the broadcaster but it'll be Mediaworks, not the National Party, that'll face the possible punishment.
Meanwhile a legal expert says there's nothing inconsistent about a radio show involving the Prime Minister being cleared by the Broadcasting Standards Authority, but being found in breach of broadcasting law by the Electoral Commission.
A commission ruling due out today has found the RadioLive show hosted by John Key last September was an election programme and therefore a prohibited broadcast.
A Broadcasting Standards Authority complaint laid about the show last year was knocked back.
But electoral law expert Graeme Edgeler says this ruling by the Electoral Commission doesn't undermine the BSA's credibility as it isn't a broadcasting standards matter.
John Key hosted the hour-long show interviewing the likes of Richie McCaw, Sir Richard Branson and Sir Peter Jackson.
The Electoral Commission believes the RadioLive show broke the law.
The commission's decision is contrary to an earlier one made by the Broadcasting Standards Authority and the police will now decide whether to prosecute the broadcaster which could be fined up to $100,000.
The show was aired during the three month strict advertising control period.