Ex-MPs probably ineligible to get pensions: Lawyer who started constitutional saga

The man who sparked the Australian Parliament's citizenship scandal says he believes there are many former politicians receiving generous pensions despite not being entitled to serve because they were dual citizens.

The lawyer who started the constitutional saga says that there are probably a mumber of former MPs who should not be receiving a pension. Source: AAP

West Australian lawyer John Cameron outed Greens MP Scott Ludlam as a New Zealand citizen in July.

Since then another seven politicians found to be dual citizens have quit, and more are expected to follow.

"For every one who has been identified now, there are probably three to four from the past receiving pensions to which they are not entitled," Mr Cameron told ABC radio on Thursday.

"We are talking about very significant sums of money that will never be repaid."

Mr Cameron started pursuing Julia Gillard and Tony Abbott in 2011, both now former prime ministers, for evidence they had renounced their UK citizenship but was dismissed by the High Court.

He wants a national corruption watchdog to be set up which could investigate citizenship matters with authority.

There had been a consensus for the past 25 years among the major parties not to raise citizenship issues about MPs, he claimed.

Mr Cameron defended his role in sparking the crisis, saying making a false declaration to a Commonwealth officer was a criminal offence potentially punishable by imprisonment.

He praised Mr Ludlam, saying he deserved credit for resigning. Otherwise the matter would have stayed buried, he said.

"I don't think it's a big ask to expect that those who make up the law in fact observe our laws," Mr Cameron said.