Seib quotes Navarro as saying: "Let me correct a mistake I made.In conveying that message I used language that was inappropriate".
Navarro offered the apology at a Wall Street Journal conference Tuesday, the Journal's Gerald Seib tweets.
Trudeau said he had reiterated to Trump, who left the G-7 meeting before it ended, that tariffs would harm industries and workers on both sides of the U.S.
Larry Kudlow, the White House economic adviser, also characterized Trudeau's remarks as a "betrayal".
Navarro lashed out on Fox News following a multi-day tirade by Trump and his administration over trade and Canada's response to tariffs imposed by the U.S. "The Canadians will regret this action by their prime minister", Gorka said.
The remarks caused Trump to bash the Canadian leader on Twitter and refuse to sign the official G7 communique - a mostly symbolic but important gesture. I really did, other than he had a news conference, that he had because he assumed I was in an airplane and I wasn't watching.
For dairy products, which has been the focus of Trump's anger, those tariffs range from almost 300 per cent for excess imports of butter and cream to 270 per cent for certain dairy powders to 240 per cent for cheese, whole milk and yogurt.
The president said he was annoyed by Trudeau's comments about not letting Canada get pushed around.
Kudlow said Trudeau had engaged in a "a sophomoric political stunt for domestic consumption" and should apologize.
On Monday, MPs in the House of Commons approved a motion denouncing Trump's name-calling tirade and endorsing Trudeau's decision to stand his ground against US tariffs and tweeted presidential threats.
The fight isn't just with Trudeau and Canada but with the best allies of the U.S., Democratic Senator Dianne Feinstein of California said on CNN.
"I don't know where we're getting the people to actually make this happen ... which will increase inflation and costs [for Americans]".
"There are always irritants in relationships", Pompeo said while in Singapore for a summit between Trump and North Korea's Kim Jong Un.
Trump followed up on Sunday with tweets calling free trade with Canada "fools trade" and said Trudeau "acts hurt when called out".
The U.S.is not seeking dismantlement of supply management, just greater access and the end of a Canadian system of pricing milk protein ingredients that is undercutting global prices, said Tom Vilsack, chief executive of the U.S. Dairy Export Council and a former U.S. Agriculture Secretary.