Dual citizen MPs have debts waived

Half a dozen MPs who lost their jobs won't have to repay their salaries and expenses to taxpayers after it was found they acted "in good faith".

A collection of government departments reviewed the circumstances of six of the various MPs found ineligible to sit in parliament and recommended the debts be waived.

"(The review found) all parliamentarians performed their duties in good faith for a proper purpose and that it was difficult for individuals at the time of nomination to know that they were ineligible for nomination," Finance Minister Mathias Cormann said on Thursday.

"These debts include salaries, superannuation and electorate allowances, as well as non-salary expenses, such as, staff expenses, office expenses and travel expenses."

Greens Scott Ludlam and Larissa Waters, Nationals MPs Barnaby Joyce and Fiona Nash, and One Nation's Malcolm Roberts will have their debts waived after they were found to be dual citizens and therefore ineligible to sit in Parliament.

Rodney Culleton was also found ineligible because when he was elected he had been convicted of a crime with a sentence greater than 12 months.

That conviction was later quashed, and his debt will also be waived.