Conservative Sen. Mike Duffy says he will repay the taxpayer-funded housing allowance he’s been collecting, blaming “unclear” Senate rules for making him believe he was entitled to the money.

Duffy said Friday he “may have been mistaken” when he filled out Senate forms to claim the housing allowance given to senators whose primary residences are located more than 100 kilometres from Ottawa.

“What we’ve got here is a case where the rules aren’t clear,” Duffy told CTV Atlantic.

“I filled in a form that the Senate has, which I may have filled in incorrectly. And if I did that…anyway.”

Duffy said he will return the funds “even though I don’t believe I owe the money.”

The senator has claimed $42,802 for living expenses in the Ottawa area since September 2010. Senators who live more than 100 kilometres from the capital can claim up to $21,000 in housing and meal expenses annually.

Duffy has repeatedly claimed his primary residence is a cottage in Cavendish, P.E.I., even though he has also lived in the Ottawa area for decades.

Questions were raised about Duffy’s residence claims after it was revealed that he did not have a valid health card in P.E.I. He also wasn’t on the voters’ list in that province in 2011, but rather voted in the Ontario provincial election.

Duffy’s office tried to expedite his health card application in P.E.I. after the Senate asked all members of the upper chamber to submit documents proving where they lived by Jan. 31.

The request was denied because it was considered to be an application for a brand new health card, which is subject to a three-month waiting period.

Duffy said Friday he did not have a P.E.I. health card because he underwent open heart surgery at the Ottawa Heart Institute and was advised by doctors there to continue seeing the same specialists in Ontario.

“They didn’t want, with some of the experimental stuff that they’re doing, to get into some kind of a negotiation with P.E.I. over how much P.E.I. was prepared to pay for my health care for my heart,” Duffy said, noting that his home province does not have a cardiac care centre.

Charlottetown-based newspaper The Guardian also revealed that Duffy and his wife are considered non-resident owners of their Cavendish cottage and must pay higher taxes as a result.

P.E.I. law states that an individual must live in the province for 183 consecutive days in a taxation year to be considered a resident.

But Duffy said his schedule makes it impossible for him to be on the island 183 days in a row.

“No parliamentarian lives on P.E.I. for 183 consecutive days,” he said. “My heart is in P.E.I. but my job is in Ottawa. I travel extensively, as you know.”

Duffy said P.E.I.’s residency law “does not apply to the Parliament of Canada” and doesn’t disqualify him from representing the province in the upper chamber.

“I am entitled to be a senator from P.E.I. I meet all the constitutional requirements. There is nothing in the rules anyway that says how much time you should spend on P.E.I.”

Duffy stressed that he claimed the housing allowance “in good faith” and under the belief that he complied with the rules. But after discussing the issue with his wife, he decided to pay back the money.

“It’s really taken on a life of its own. It’s unfortunate,” he said of the controversy that has been dogging him for weeks.

He said constant questions about his residency were getting in the way of the work he’s trying to do in the Red Chamber.

“All of those things get sidetracked; you can’t get on with the business of building a better Canada when you spend all of your time answering questions about the really arcane rules of the Senate,” he said.

“Canadians know Mike Duffy. They’ve known me for years and they know that I would never do anything that was inappropriate and I would never, ever take advantage of my position.”

But NDP’s ethics critic, Charlie Angus, said Duffy’s repayment should not absolve him of accountability.

“If you break the rules, saying ‘I’m sorry’ just doesn’t cut it. There must be consequences,” Angus said in a statement. “What discipline will the Senator face?

“If any forms were falsified in order to try and get extra expense money, the Senate should immediately refer the matter to the police,” he added.

While the Senate is asking all members of the upper chamber to provide proof of their residency, it also brought in an independent auditor to pore over the expenses of three senators: Duffy, Liberal Mac Harb and Independent Patrick Brazeau.

Conservative Sen. Pamela Wallin is also being audited for her travelling expenses.