Gary Gray.

Challenge has no support inside parliament ... Gary Gray. Photo: Stefan Postles

THE Special Minister of State, Gary Gray, has accused retired MPs who are threatening a High Court challenge to win back their perks of an "outrageous cash grab".

The Association of Former MPs of the Parliament of Australia is reportedly planning a constitutional challenge to recent reforms which cut former MPs' entitlements to taxpayer-funded travel and delinked superannuation payments for retired politicians to wage increases for members of the current parliament.

The group has reportedly asked the Commonwealth to fund the challenge, which would be made on the grounds that the constitution forbids acquisition of property without "just terms," the section made famous by the 1997 film The Castle.

But speaking on Perth radio today, Mr Gray ruled this out.

"We'll say no. Both sides will say no. Mr Abbott will say no. Prime Minister Gillard will say no and they've been in the parliament for long enough to know why the parliament has taken the decisions it's taken over the years and ... neither side of Federal Parliament would be supporting this gesture at all," he told 6PR.

"This is simply an outrageous cash grab by these retired politicians," he said.

Mr Gray said he suspected the group represented "very few" former politicians.