"With a heavy heart I have submitted my letter of resignation to the Prime Minister as a member of Cabinet," Wilson-Raybould said.

Jody Wilson-Raybould. [File photo: IC]

Her resignation came amid ongoing parliamentary investigation into whether Trudeau or anyone in his office tried to have Wilson-Raybould abandon the prosecution of a case against SNC-Lavalin when she was justice minister and attorney general.

Conflict of Interest and Ethics Commissioner Mario Dion said on Monday that he was to start the investigation into the allegations as he believed the law might have been contravened in this case.

It also came one day after Trudeau said Wilson-Raybould's continued membership in his cabinet as an indicator to Canadians that she was not unhappy with his government.

"Her presence in cabinet should actually speak for itself," the prime minister said Monday.

Trudeau also said he "welcomes" the Conflict of Interest and Ethics Commissioner's newly-announced investigation.

Last Thursday, Canadian newspaper The Globe and Mail reported that as attorney general, Wilson-Raybould came under pressure from the Prime Minister's Office to override the decision of the public prosecution service shelve court proceedings against SNC-Lavalin in favor of a negotiated settlement without trial. The company faces charges of bribing Libyan officials between 2001 and 2011 in exchange for contracts.

Canadian opposition parties have called for parliamentary investigation on alleged interference by Trudeau's office in the SNC-Lavalin case.