The Senate has asked Ottawa law firm Auger Hollingsworth to review the cases of seven former senators determined to have wrongly-claimed expenses and decide whether to launch further legal action.

The firm will spend the next few weeks determining whether it’s in taxpayers’ interest to attempt to collect on those who former Supreme Court justice Ian Binnie said owed money and who have yet to repay.

Binnie’s review, completed earlier this year, found 30 senators had wrongly claimed a total of $991,900. Most subsequently repaid the amounts.

But seven others, said to owe a total of $528,553, still have yet to repay. As they have all retired, the Senate cannot garnishee their wages and must instead consider civil action.

Lawyer Brenda Hollingsworth, who is leading the review, will advise Senate law clerk Michel Patrice and the Committee on Internal Economy whether the prospects of collecting in court is worth spending money on the litigation.

The full acquittal of Senator Mike Duffy could encourage some of the allegedly delinquent senators to defend any attempt to recover the amounts they are said to owe. A civil claim of wrongful expense claims would have to be proved in court, though not to a criminal standard.

A further complication Hollingsworth must weigh is the complexity of collecting from the late Liberal senator Rod Zimmer, who died earlier this month owing the Red Chamber $176,012.

That could draw the Senate into a messy probate challenge of Zimmer’s will, potentially featuring his wife, Maygan Sensenberger, a much-younger actress who was once charged over an incident involving Zimmer on an Air Canada flight.

Those that still owed money, according to the Senate, as of May 31, 2016:

Sharon Carstairs $   7,527.00
Marie-P. Charette-Poulin $125,828.00
Rose-Marie Losier-Cool $110,051.00
Don H. Oliver $  24,738.00
Bill Rompkey $  17,292.00
Gerry St. Germain $  67,105.00
Rod A. A. Zimmer $176,012.00