OTTAWA -- One of two sitting senators who face an RCMP review of their expenses says he's "surprised" the auditor general concluded he had broken housing and travel spending rules.

Auditor general Michael Ferguson's review concluded that Sen. Pierre-Hugues Boisvenu didn't spend enough time in Sherbrooke, Que., in 2012 to make that his primary residence.

Ferguson also found that Boisvenu travelled the country doing interviews and events for his foundation, which is focused on helping victims of crime.

Boisvenu says he was travelling on parliamentary business.

He also insists the Senate rules don't require senators to live at their primary residences for a minimum amount of time.

Boisvenu says he wants to challenge the findings in the arbitration process set up by the Senate and headed by former Supreme Court justice Ian Binnie, in order to get a definition of "parliamentary business."