"On his comments, as I said, I'm going to stay focused on defending jobs for Canadians and supporting Canadian interests".
Navarro came under scrutiny Sunday for bashing Trudeau after the prime minister criticized Trump in the wake of the G-7 summit held in Canada.
At a news conference after his meeting with Mr Kim, the President said the Canadian leader must not have realised that Mr Trump had televisions on Air Force One, allowing him to monitor Mr Trudeau's news conference at the end of the G7 summit.
Bruce Heyman, the former U.S. Ambassador to Canada, on Monday slammed Donald Trump's treatment of Justin Trudeau, and Canada in general, demanding the president apologize for his surrogate's claim there's a "special place in hell" for people like the Canadian prime minister.
Navarro also said Trudeau is "weak and dishonest".
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.
Navarro's interview followed another by National Economic Council Director Larry Kudlow, who called Trudeau's statement as "diplomatic betrayal".
Picture of Trump, G7 leaders goes viral
It showed a seemingly glowering German Chancellor Angela Merkel and several other leaders appearing to confront a seated Mr Trump .
Trump arrived in Singapore on Sunday in preparation for his meeting with Kim after cutting short his trip to Quebec for the G7 summit, where he met the leaders of Britain, Canada, France, Germany, Italy, Japan, and the EU.
"Canada does not believe that ad hominem attacks are a particularly appropriate or useful way to conduct our relations with other countries", Foreign Affairs Minister Chrystia Freeland responded.
On Tuesday Trump reiterated his belief that the United States is "being taken advantage of by virtually every one" of the countries in the G7. And every Canadian PM knows US presidents have enormous power to affect Canadians' lives, even accidentally.
Bruce Heyman, a former U.S. ambassador to Canada, said Mr Navarro had "crossed a line". "It seems to me that despite our frictions with Canada - and we have had trade disputes in the past and we have issues with the Canadian subsidies right now - that we need to recognize that Canada has been a close friend, a reliable ally and is one of our biggest trading partners".
"I know it didn't look friendly", Trump said.
In reality, the United States has a small surplus with Canada when goods and services are considered - $341.2 billion to Canada's $325.9 billion, according to 2016 statistics from the USA trade representative.
He said, "Yes, absolutely".