New Zealand First leader Winston Peters says he would find it difficult to trust National’s John Key.

Key has already ruled out working with NZ First after the election, and Mr Peters’ comments today make it even more unlikely the two parties could forge an agreement.

Speaking on TV One’s Agenda programme today Peters said the revelation that Key held Tranz Rail shares at the same time he was attacking the rail buyback plan raised “serious doubts” about whether he could trust National’s leader.

Key apologised last week after it was revealed his family trust once held twice as many shares in Tranz Rail as he had previously acknowledged.

He has previously said he sold the shares as soon as he realised he was involved in a political issue.

“He ruled me out before I even got to have a hearing at the privileges committee and I know that he did trade in shares while he was asking questions on Tranz Rail,” Peters said.

“And if the test is to look a man in the eye and trust him, I doubt if I can do that now.”

Peters is turning around Key’s own credibility test.

When Key ruled not working with NZ First after the election, he said he would have to be able to look his colleagues in the eye and trust them.

However, Peters did not completely rule out working with National when he was questioned on Agenda.

“I’m not going to waste this campaign and the next six weeks talking about what we might do,” he said.