Seven retired senators are facing legal action to recoup cash they owe for illegitimate expense claims.

The total amount owed tops $528,000.

An eighth retired senator did not receive notification on time and has been granted an extension to repay.

The deadline to repay monies owed was end of day Thursday.

All sitting senators are paid up. Those members could have faced other penalties, including garnisheed wages.

The chair and deputy chair of the standing committee on internal economy, budgets and administration, senators Leo Housakos and Jane Cordy, issued a statement: "The Senate has been clear about its intention to take legal action in order to recoup any monies owing by non-sitting senators," it read. "To that end, the Senate law clerk has been instructed to seek outside legal counsel to initiate such action."

Outstanding money owed

The senators who still owe money are: