Justin Trudeau stopped in the Town of Bracebridge as part of his campaign for the leadership of the federal Liberal party on Feb. 15 2013. (Corey Wilkinson/QMI Agency)

OTTAWA - MPs moonlighting on the public dime should at the very least return a portion of their hefty salaries if their second careers conflict with their parliamentary duties, says a watchdog group.

The Canadian Taxpayers Federation says that when Parliament is in session MPs have a duty to represent their constituents and not tour the country to line their pockets with a second income. MPs earn $158,000 annually plus other perks and benefits

The issue has come to the fore after self-confessed millionaire and leadership candidate Justin Trudeau padded his bank account on the speaker's circuit.

Since becoming a Liberal MP in 2008, Trudeau has socked away nearly $280,000 in fees he charged schools, unions and others to hear him yammer - on top of hundreds of thousands of other dollars he banked before becoming an MP.