Prime Minister John Key is refusing to appear on a televised leaders' debate with anyone other than Labour leader Phil Goff.



Key was invited to participate in a TV3 debate with the leaders of all parliamentary political parties but refused.

Goff will only participate if Key does.



The debate is now canned because the leaders of the two biggest political parties would not be involved.



Three years ago Key and then Labour leader Helen Clark agreed to only participate in presidential style debates between the two of them.



Key said he did not see any point debating with those not in the running to become prime minister.



"At the end of the day the vast bulk of New Zealanders will either be voting for Labour or National and so my view... is that it makes sense actually to have those one-on-one debates, give New Zealanders the opportunity to see who shapes up as the best prime minister to lead the country."



The only two contenders for the job were himself and Goff, Key said.



National had proven in Parliament that it could work with other smaller political parties, he said.



Goff said he would participate in any debate that Key was involved in.



"If he's not going to be there then that takes away the main debate between the two major parties, he should be there."

He would be involved in five or six other debates.



Neither Key nor Goff knew whether their offices had discussed the issue.