LNP candidate and former Howard government minister Mal Brough has again denied he approached billionaire Clive Palmer to fund a legal case against his political rival, Peter Slipper.

On Thursday, Queensland mining magnate and Palmer United Party founder Mr Palmer said he met Mr Brough in April last year.

Mr Palmer said during the meeting Mr Brough outlined a potential sexual harassment case by James Ashby against former parliamentary speaker, Mr Slipper.

Mr Palmer says Mr Brough was seeking funds to pursue the case.

"He said to me, 'we need to destroy Peter Slipper'," Mr Palmer said.

The allegation that Mr Palmer was asked to help fund Mr Ashby's sexual harassment case is not a new one.

Mr Slipper raised it under parliamentary privilege in June as he delivered a pre-emptive valedictory speech.

Mr Brough held a media conference on Thursday to again deny the claims.

"I just want to say straight out that I deny the comments that have been made today by Mr Palmer," he said.

He says he did meet Mr Palmer, but he has accused the mining boss of changing his story about what happened.

In his speech to Parliament in June, Mr Slipper said Opposition treasury spokesman Joe Hockey also accompanied Mr Brough to the talks with Mr Palmer.

Mr Palmer says he brought up the claims again on Thursday to set that point straight.

"I just want to make it absolutely clear, I think I've got a moral duty and a responsibility to Mr Hockey and his family and indeed the Liberal Party to make it absolutely clear that Mr Hockey played no role in these discussions," he said.

"He walked past at the end of our discussion with Mal Brough and merely sat down and had a coffee."

Mr Brough is the Coalition's candidate in the Queensland seat of Fisher, which Mr Slipper is contesting as an independent.

In dismissing that case late last year a Federal Court judge ruled Mr Ashby was working with Mr Brough to damage Mr Slipper's reputation.

Mr Brough and Mr Ashby reject that and the Federal Court decision is subject to appeal.