The senior federal Conservative cabinet minister from B.C. is calling on Senator Mike Duffy to resign in the wake of a growing scandal over improper repayment of expenses.

Heritage Minister James Moore, the MP for Port Moody-Westwood-Port Coquitlam, told CTV Tuesday, May 21st Duffy should resign altogether.

Duffy has already quit the Conservative caucus in the Senate after the disclosure that Nigel Wright, chief of staff for Prime Minister Stephen Harper, gave the embattled senator a cheque for $90,000 to repay expenses that may have been improperly claimed. Wright has since resigned his post.

Under pressure to provide a public explanation of what happened, Prime Minister Stephen Harper spoke to his caucus Tuesday morning in front of the media, who weren’t permitted to ask questions.

Harper said he was “not happy” and “very upset” about the conduct of some parliamentarians and of his own office, before leaving for South America on a trade mission.

“Anyone who wants to use public office for their own benefit should make other plans or better yet leave this room,” Harper said.

He said he didn’t get into politics to defend the Senate, a reference to his long-standing position it should be reformed as an elected body.

The NDP Opposition have called for an RCMP investigation and the federal ethics commissioner is investigating.

The Senate’s conflict of interest code forbids senators from accepting any gift or benefit “that could reasonably be considered to relate to the senator’s position.”

The Parliament of Canada Act specifies that senators may not receive compensation “for services rendered… in relation to any bill, proceeding, contract, claim, controversy, charge, accusation, arrest or other matter before the Senate or the House of Commons.”

Those who offer such compensation may be liable to imprisonment for up to a year.

Two other senators have also quit the Conservative caucus amid ongoing expense audits.

Criticism of the ethical failures of Duffy and Wright have ruffled Conservative ranks across Canada, including in B.C., where the party holds 21 seats.