Liberal members of a parliamentary committee have protected a fellow MP from their party from a grilling over allegations he performed lobbying work while still sitting in the House of Commons.

The Conservatives first raised questions earlier this month about Derek Lee's work for a Toronto law firm, saying a description on the firm's website of his activities show they constitute lobbying.

Lee, the Liberal MP for the Toronto area riding of Scarborough-Rouge River, appeared before the government operations committee on Thursday and stated he is not a lobbyist, but argued the committee was the wrong parliamentary body to examine his conduct.

Meanwhile, Liberals Marlene Jennings and John McKay took up time with long speeches on why Lee should instead appear before the House procedures and affairs committee, despite government operations' high-profile hearings on lobbying allegations against former Conservative MP Rahim Jaffer.

The tactic sparked fury from Conservative members, who have been lambasted by opposition parties this week for the government's new policy barring ministerial staff from appearing before committees.

Conservative MP Chris Warkentin, the committee's vice-chair, argued that Lee's Liberal colleagues did him a "great disservice" by preventing him from clearing up the matter and causing "more confusion, and more suspicion and more frustration.

"By being sabotaged by your own legal team today, you've have allowed there to be more questions and more suspicions than there was when we showed up," he said.

NDP member Pat Martin, in turn, accused the Liberals of conducting the same sort of high-handed behaviour that Parliament has seen from the government with its staff committee appearance ban.

The House has been embroiled in a debate over ethics and lobbying rules since it emerged that Jaffer was contacting government members about access to federal money for alternative-energy projects. Jaffer, who is not registered as a lobbyist, denied his work constituted lobbying.

Lee, who's been an MP since 1988, disclosed to the federal conflict of interest commissioner that he receives "business income" from Sun & Partners. According the commissioner's website, Lee is in compliance with government rules and regulations.

With files from The Canadian Press