The Senate says that seven expense claims totalling $16,995 which came up during Sen. Mike Duffy's criminal trial weren't eligible under the upper chamber's spending rules.

Months after Senator Mike Duffy was acquitted of all 31 charges of fraud, breach of trust and bribery, Senate officials want Duffy to pay back $16,955 in what they call ineligible expenses.

Senator Mike Duffy's expenses may still be subject to a review by the Auditor General of Canada, despite the fact that he was cleared of all 31 criminal charges.