Both major political parties are distancing themselves from a call to stop parliamentary pensions while ex-MPs and senators hold diplomatic posts.

Former treasurer Joe Hockey has been mooted as Australia's next ambassador to the United States.

It has been reported Mr Hockey could earn up to $450,000 a year if he combined the ambassadorial salary with 50 per cent of his parliamentary pension — up to an extra $90,000 a year.

Independent senator Nick Xenophon on Sunday urged Mr Hockey to rule it out.

"I just want to help Joe Hockey fulfil his dream of ending the age of entitlement, by Joe Hockey setting an example for the rest of us," he said.

But in response to questions from the ABC, the Coalition and Labor refused to support such a change.

"We do not comment on the circumstances of an individual member or senator," a spokesman for Special Minister of State Mal Brough said.

"Members who were elected to parliament at the 2004 election or later are not entitled to a parliamentary pension.

"This affects more than 70 per cent of current parliamentarians."

Shadow special minister of state Gary Gray said rules about benefits should be left to the Remuneration Tribunal, which is an independent authority.

"As a general proposition, Labor believes whatever the Remuneration Tribunal determines should be final," Mr Gray said in a statement.

"This should be the case for current MPs and those asked to serve in other salaried offices such as diplomatic posts.

"Double dipping is wrong, but it should be the case for current and future post-service pensioned MPs and senators that these matters should be determined by the independent Remuneration Tribunal."

The Abbott government came under fire earlier this year after announcing changes to its paid parental leave policy, which would stop parents "double dipping" by accessing both work and government schemes.

Mr Hockey has long been an advocate of reducing government payments and used his valedictory speech last week to again call for an end to the "age of entitlement".