Labour leader David Cunliffe told NewstalkZB in April that he would be happy to debate Prime Minister John Key "anytime, any place, anywhere, I'll even do it on Mike Hosking's show."
NewstalkZB has posted the clip from an interview with host Tim Fookes which followed Mr Key's challenge to Mr Cunliffe for a televised debate on housing affordability.
After Mr Cunliffe agreed to the challenge, Mr Key retracted it saying he had been referring to the usual TV debates during the election campaign rather than a special one-off.
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Mr Cunliffe's comment was made in that context rather than in relation to an election debate.
This week it emerged that Labour had objected to TVNZ's choice of its Seven Sharp presenter Mr Hosking as its election debate moderator because of pro-National comments he had made, including while acting as MC for Mr Key's 2013 State of the Nation address in 2013.
Mr Cunliffe said Hosking's apparent endorsement of National "raised some questions that TVNZ will want to very carefully consider."
Mr Key had challenged Mr Cunliffe to a debate on housing affordability at his weekly post-Cabinet press conference in April, saying:
"If David Cunliffe wants to have a bit of a chat on nationwide TV about it, I'm more than happy to do so. We'll call it the first debate. I'm looking forward to it."
Mr Cunliffe said he would gladly accept any such invitation. "I can't think of a more important topic to be debated publicly, and I think it's my obligation as leader of the Opposition to rise to that challenge."