Last week, the Globe and Mail newspaper alleged that the prime minister's office had pressured former justice minister and attorney general Jody Wilson-Raybould to intervene in the case against the Quebec-based engineering giant.
In a letter addressed to Prime Minister Justin Trudeau, Wilson-Raybould said she is in the process of obtaining advice on the topics she is legally allowed to discuss.
CTV News has not independently verified the story, and Trudeau has denied it.
Monday, he said in Vancouver that he'd told Wilson-Raybould that any decision on the subject was hers alone.
"We welcome the ethics commissioners investigation this is an issue that has been much talked about over the past few days, and i think its extremely important that Canadians can continue to have confidence in our system", said the Prime Minister.
Jody Wilson-Raybould made her resignation letter public on February 12, 2019.
"I have reason to believe that a possible contravention of section 9 may have occurred", Dion wrote in a letter to NDP MPs Nathan Cullen and Charlie Angus, who filed the complaint.
Conservative Leader Albert Scheer has led the charge to haul Trudeau's aides and top members of his party in front of an emergency meeting of the justice committee for what he calls "unprecedented" attempts at influencing a criminal proceeding.
Speaking in Vancouver, the prime minister said he "welcomes" the probe into allegations of improper conduct by government officials.
Wilson-Raybould was shuffled out of the justice portfolio last month, and is now the minister of veterans affairs, a move widely seen as a demotion.
Her decision follows a week of scrutiny following bombshell allegations of political interference reported by The Globe and Mail.
SNC-Lavalin was charged with paying out $48 million in bribes to Libyan officials in the decade leading up to the NATO-led overthrow of Muammar Gaddafi's government in 2011, payments meant to influence government decision-making, though the company was also charged with defrauding Libyan companies of about $130 million.