RETIRED federal MPs are threatening a High Court challenge to claw back millions of dollars in generous perks, including lifetime Gold Pass and superannuation payments.

The umbrella group representing former MPs has asked the Commonwealth to fund the legal challenge, which could result in windfall gains for up to 400 parliamentarians.

But one federal Senator has savaged the move to claw back perks, saying it makes politicians look like “a pack of greedy bastards”

A successful court ruling would also flow through to some current MPs who stand to lose about 60 per cent of annual Gold Pass perks when they retire.

Respected legal figure and former attorney-general Bob Ellicott has offered to spearhead the constitutional test case, which comes after a series of landmark reforms passed parliament earlier this year - including slashing the Gold Pass entitlement from 25 domestic flights a year to 10.

The changes also "delinked" superannuation payments for retired MPs from hefty wage increases which flowed through to the 226 MPs and senators in the current parliament to prevent so-called "double dipping".

The Association of Former MPs of the Parliament of Australia (AFMPA) believes the changes breach the "just terms" clause of the Constitution - made famous in 1997 film The Castle.

The association wrote to the Commonwealth about a month ago seeking funding for a "test case" in the High Court.

The prospects of a messy legal challenge has incensed some former and current parliamentary figures, who believe it will add to a "snouts in the trough" perception.

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Victorian DLP Senator John Madigan launched a blistering attack on the move, saying MPs were well paid and well looked after in retirement.

"What a mockery it makes of the battlers out there, and people taking risks with their capital and creating jobs out there,” he said.

"The average bloke on the street would be thinking ‘what a pack of greedy bastards’.”

Senator Madigan said he was "speechless” about the move to seek a High Court challenge.

He also hit out at the recent pay rise for politicians, worth about $44,000 for most MPs, which he spoke out against at the time.

“The bloody pay rise adds up to more than what a lot of people in my street get paid in a year,” he said.

“They think I’m part of it. They think we are part of it.

“People come up to me and say, ‘you are one of those greedy bastards’.”

Community outrage over the generous perks paid to retired MPs led to the reforms.

More than 25,000 free flights were taken by retired MPs and their families over the past decade, with former Speaker Ian Sinclair taking more than 750 flights costing over $250,000. Between July and December last year, Mr Sinclair and his family took 55 free flights costing $19,000, while former Liberal minister Geoff Prosser cost taxpayers $24,000 including $10,378 for three trips to Broome, where he has a holiday home.

A raft of former MPs are supporting the legal challenge, including former Howard government minister John Moore and long-serving Liberal senator Grant Chapman.

Last night, Mr Chapman confirmed the association's intent to pursue action in the High Court.

"This is a constitutional issue that needs to be resolved," he said.

- with Matthew Johnston

Originally published as Former MPs want their perks back