Don Brash wants to fast-track a hearing on Peter Ellis' child sex abuse convictions.

Ellis, 61, served seven years of a 10 year jail sentence for abusing seven children at the Christchurch Civic Creche in 1991.

He was freed in 2000 having always maintained his innocence.

The original 16 charges were based on the preschoolers' testimony of ritual abuse and torture.

Three convictions were overturned in 1994 after one of the children said she lied.

Ellis now has cancers, with reports he may only have three months to live.

He has now filed an application for leave to appeal to the Supreme Court.

It is being asked to consider whether there was a miscarriage of justice due to the children's evidence being improperly obtained, a lack of expert evidence and unreliable expert evidence at trial.

Former National leader Brash previously campaigned for an inquiry into the case. He told Heather du Plessis-Allan it's a serious miscarriage of justice.

"It just doesn't hang together. And frankly neither the court systems nor indeed successive governments, both National and Labour, have acquitted themselves well."

Brash says that Ellis was charged even though four women who were charged with him were not prosecuted with him in the end.

He says the only alternative to an inquiry would be if the Government asked the Governor-General for the Prerogative of Mercy. 

The petition that Brash set up over this case sparked a lot of interest, but nothing was ever done of it. 

"It's very strange. It's very depressing," Brash says. 

- with content by RNZ