Nova Scotia senators' expenses cost Canadian taxpayers close to $2.3 million in 2012, CBC News has learned.

There are 10 senators in Nova Scotia. Among them is the leader of the Senate opposition and the deputy speaker.

Senators are allowed to charge for office expenses, travel and living in Ottawa.

A large part of senators' expenses are travel costs. Senators can ride for free on Via Rail trains, but because most of them have to travel to and from Ottawa weekly, they mainly travel by plane.

On average last year, Nova Scotia senators spent about $100,000 each in travel costs.

Some spent more, like Senator Terry Mercer.

He said that's because he had additional duties as the former Liberal caucus chair.

"I don't feel embarrassed about any of them. I'm quite happy that I was able to do what I was able to do when I was caucus chair. We continue to work to make sure that we keep expenses as low level as possible," he said.

Senators are required to live in their home provinces and travel to Ottawa.

The Senate is auditing its members to ensure they live where they say they do after media reported three of them spend most of their time in the National Capital Region but claim they live elsewhere and collect a living allowance worth up to $21,000 a year.

CBC News contacted each Nova Scotian senator's office.

All of them said they have homes, driver's licences and health cards in this province. The $2.3 million in expenses doesn't include the senators' salaries.

Their pay cost close to $1.4 million.