The prime minister is defending yet another senator who has come under scrutiny for her expense claims.

Stephen Harper says he's reviewed Conservative Sen. Pamela Wallin's travel bills and they appear to be in line.

Harper says the amount Wallin charges taxpayers to commute between Ottawa and her home province of Saskatchewan mirrors what other parliamentarians from the area bill each year.

Records show that the amount Wallin bills specifically to travel to Saskatchewan from Ottawa pales in comparison to what she cites as "other" travel.

In an interview with CKOM radio in Saskatchewan, Wallin says that's because she often returns to the province from places outside of Ottawa.

Wallin, whose expenses and housing records have raised questions about whether she actually lives in Saskatchewan, says she spent 168 days there last year.