TV3 political commentator Linda Clark acted for Shane Taurima in the contentious inquiry into his Labour party activities while he was an executive at TVNZ.
Clark's employers at law firm Kensington Swan refused to comment but well-placed sources confirmed she had represented Taurima when he was responding to the inquiry.
She had no role in ongoing discussions between Taurima and the Labour Party about its decision to shut him out of the Tamaki Makaurau candidate section process, sources said.
Clark is a former host of the National Radio's Nine to Noon show, and TVNZ political editor before moving into the law.
She has specialised in providing clients advice on dealing with politicians and at the same time has revived her political commentary career through TV3 current affairs shows such as The Vote and The Nation.
Her joint role of player and commentator highlights something of a trend for television current affairs programmes.
Shows like The Nation and Q&A hire pundits who can be either independent, politically or professionally linked, or a mixture.
Conflict of interest rules still apply and they rely on people declaring those potential conflicts.
But TV3 seems to have a "don't ask don't tell" policy around Clark declaring conflicts of interest with her clients at Kensington Swan.
On Tuesday Prime Minister John Key questioned Clark's role providing media training to the Labour leader while acting as a public law specialist for the Wellington law firm of Kensington Swan.
TV3 news boss Mark Jennings said that Clark had never let him down in declaring conflicts.
But after Key's comment he was "rethinking" TV3 pre-election coverage for the Nation and use of Clark. The law firm's website points to her role as a political commentator.
Kensington Swan communications spokeswoman Julia Kidd said Clark performed the normal roles of public law specialist.
Asked if public law specialists also provided media training, as the Prime Minister claimed she did for David Cunliffe, Kidd declined to comment.
Jennings said he would continue to review Clark's involvement in TV3 programmes on a case-by-case basis. The Nation is 100 per cent funded by taxpayers.
Clark has not yet responded to a request for comment.