Act leader Rodney Hide's brand is "toxic" and "people don't like him", says the man who wants his job - his old mate Don Brash.

The former National Party leader upset his usual mates yesterday when he described Prime Minister John Key as "mooching" the country into debt then saying he wanted Hide's job.

Brash also raised the stakes for Act by saying he might launch his own party if he doesn't get Hide's job.

Brash's enthusiasm for the job also brought speculation that former MP and Auckland mayor John Banks might challenge Hide for Act in the coveted Epsom electorate. Banks did not return calls yesterday.

A new vehicle by Brash would compete with Act for right-wing members and funding - and be the second new political party to emerge in the run-up to this year's election.

Former Maori Party MP Hone Harawira will launch a new party this Saturday that claims to be an "independent" voice for Maori.

Brash yesterday said Hide had asked him to be co-leader, but he had turned him down.

Brash described Hide as a personal friend, then he said: "His brand has become toxic. People don't like him. I have to assume that's a significant reason the Act Party vote is fluctuating around the margin of error."

Brash said it was partly scandal that harmed Hide's image. First, Hide lost his "perk buster" image with the taxpayer-funded trip around the globe with his now-wife Louise.

Then the party was damaged when it emerged law and order spokesman David Garrett had taken name suppression to hide his conviction for stealing a dead baby's identity for a false passport.

Brash admitted he was not a member of the Act Party and was still a member of the National Party.

Hide poured scorn on Brash's claim of being offered the co-leader's job. He said he had offered to pay Brash's membership if his friend joined the Act Party.

"He wanted to be leader. I said the way you become the leader or co-leader is to join the party and work your way up."

He said Brash was too old for the job. "We're looking forward to the next generation of leaders and Don has had his shot with National. It's hard to see him contesting the 2014 campaign."