Canadian government officials are trying to determine whether the Canadian unit of General Motors had delayed the recall of some cars, breaking the law in doing so, after the U.S. fined the parent company $35 million for its delayed response.

Transport Minister Lisa Raitt said in the wake of the U.S. move to fine General Motors for not recalling cars with faulty ignition switches as soon as it knew about the problem, she instructed her officials to get answers from GM Canada.

"Having seen what has developed in the United States I've gone back to my officials to go back to GM Canada and ask them when did they find out. Did they find out at the same time as GM in the U.S. told the world or did they know earlier than that?" Raitt told reporters on a conference call.

"I need to get that information and that answer from GM Canada before we move any further because, as you know, if they had that information and didn't put the recall in place, then they could be in violation of the Motor Vehicle Safety Act," she said.

GM Canada began its recalls in February with 235,855 vehicles affected by faulty ignition switches. It issued three more recalls this week for 181,500 vehicles for various reasons.

In the latest recall, issued Friday, it said it had put a hold on 500 full-size pickups and SUVs from the 2014 and 2015 model year because of a potentially faulty supplier part in the sensing and diagnostic module that controls the vehicle air bags. Those vehicles had not yet left the dealer lot.

GM response

Asked to comment on Raitt's remarks, GM Canada said it notified Transport Canada about the initial ignition switch recall on Feb. 7 of this year, the same day its parent company notified the U.S. regulator.

"GM Canada has and continues to work closely with the federal vehicle safety regulator Transport Canada to ensure the lines of communication are open.  We will continue to offer our full cooperation with the federal government as we work through these difficult issues," GM said in an email to CBC.

GM has issued an unprecedented 29 recall notices for a record number of vehicles this year. The most high-profile recall was of cars with defective ignition switches, linked to at least 13 deaths.

The problem was originally noticed by GM more than a decade ago, but the first recalls began only in February of this year, despite years of consumer complaints.

Even though it is clear GM as a company delayed its response, Raitt said it was important to determine separately when GM Canada knew before being able to take any action under Canadian law.

"In order for us to have a good case to prosecute under, it does matter when GM Canada knew," she said.

With files from CBC News