A bipartisan group of former members of Parliament is threatening a High Court fight against moves by the Government to strip them of travel and superannuation entitlements.
The Association of Former Members of Parliament of Australia - a kind of union for retired MHRs and senators - says it has legal advice cuts to the controversial Gold Pass Travel scheme are unconstitutional.
In Tuesday's Budget, Treasurer Joe Hockey announced strict new rules on the use of the taxpayer-funded travel entitlement, saying former MPs would now face a "public benefits test" when claiming a flight.
Spouses of former MPs have also been blocked from accessing the program.
The former Labor government had already put limits on the scheme amid complaints it was being abused.
The Gillard government limited former Federal MPs to 10 domestic return airfares with a family member a year.
Labor also unlinked superannuation payments for retired politicians to wage increases for members of the current Parliament, costing retired MPs tens of thousands of dollars in retirement benefits.
The association claims to represent as many as 200 former Federal MPs from all major parties.
Former WA Liberal MP Wilson Tuckey said the association had lodged a freedom of information request with the Government, seeking the advice it received when it sought to curtail the travel scheme.
He said the organisation wanted the Government to agree to cover its own costs should the former MPs launch a High Court challenge.
"There is quite significant anger about this," Mr Tuckey said.
"If Parliament wants to proceed outside the Constitution, then it is an issue."
Mr Tuckey said the organisation believed the blocking of access to the travel scheme was unconstitutional because the Gold Pass scheme could be considered a property of MPs.
Under the changes, former MPs would not be able to claim airfares if they are for private or commercial purposes.
The change is expected to save $20 million over four years. The Government will also freeze the salaries of Federal MPs and senior public servants for a year.