Kevin Rudd, Julia Gillard and Tony Abbott would lose access to their taxpayer-funded business-class travel under changes being pushed by both rogue Liberal Senator Ian Macdonald and government defector Cory Bernardi.

Senator Macdonald - who made national headlines last week when he defended parliamentary entitlements, saying politicians are not particularly well paid - has written to party leaders to flag amendments to his own government's bills to abolish the Life Gold Pass and establish a new independent expenses authority.

In the letters, Senator Macdonald says he will seek to scrap an exemption that gives Australia's former prime ministers continued access to the notorious pass, which entitles them to 10 free business-class return flights a year.

If that fails, he will seek to limit the pass to prime ministers who served a certain number of years in the top job - meaning short-serving prime ministers like Mr Rudd, Ms Gillard and Mr Abbott would likely lose out.