Mr Cunliffe confirmed this morning that his office had raised concerns about the choice of Mr Hosking for the one on one debate between Mr Cunliffe and National leader John Key because of Mr Hosking's pro-National views.
"Concerns were raised by my staff when it became apparent Mr Hosking had introduced Mr Key at his 2013 State of the Nation speech and appeared to warmly endorse him. We are in discussion with TVNZ about that and other matters."
His staff were preparing a dossier on statements made by Mr Hosking that were of concern because TVNZ had asked for evidence of the concerns Labour had raised. He refused to comment when asked if he was considering pulling out of the debate if Hosking did moderate the debate.
"I will take further advice. I'm not prepared to comment on that now."
He said Mr Hosking's apparent endorsement of National "raised some questions that TVNZ will want to very carefully consider."
When MC'ing Mr Key's State of the Nation address in February 2013, Mr Hosking introduced Mr Key by saying he had done his own state of the nation.
"As I see it, all things considered we are doing pretty bloody well ... We have bright prospects for the future, so long as you keep them in Government," he said.
Mr Cunliffe would not say whether he believed Mr Key should have similar concerns about TV3's choice of John Campbell to moderate its debate, given Mr Campbell's more left-wing leanings.
Mr Cunliffe also said he was "very surprised" by a Rugby News magazine cover featuring Mr Key dressed as an All Black and flanked by other All Blacks, including captain Richie McCaw.
" I was surprised to see it. It's not often you see a major sporting body getting involved in politics."
He did not know if the All Blacks had known about the cover or given their consent.
"I would like to know more about the background to that. I think it is a very surprising thing to see."
He would not say if he thought it was fair.
"That is a matter for the public to make up their own mind about. All I can say is I'm a passionate rugby fan, a huge All Blacks supporter and I will continue to be when I am Prime Minister."
Asked if was a bit over the top, he said: "The question of style and humility is a separate question from the question of appropriateness."
