However, Navarro says he used inappropriate language in trying to convey that message.
"I had a very good meeting with the G7", Trump said, rejecting suggestions the summit was a failure.
Appearing on "Fox News Sunday", Navarro said: "There's a special place in hell for any foreign leader that engages in bad faith diplomacy with President Donald J. Trump".
Days later, Trump said that he had left the summit at that stage and was aboard Air Force One en route to Singapore when Trudeau gave the press conference.
Donald Trump's heightened attacks on Canadian Prime Minister Justin Trudeau are raising concerns that he might follow through on threats to impose auto tariffs, a move that could devastate the vehicle industry in Canada and lead to higher US prices.
The president said he was annoyed by Trudeau's comments about not letting Canada get pushed around.
"I see (on) the television that he's giving a news conference about how he will not be pushed around by the United States".
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. We just shook hands.
Republican U.S. Senator Tom Cotton, however, said North Korea's leader could also face harsh words.
A spokeswoman for Mr Trudeau, Eleanore Catenaro, declined to comment on Mr Navarro's acknowledgement of a mistake.
Trump's statements could be merely "chest thumping", he said, but after moving to impose tariffs on steel and aluminum on the basis of national security, the threat of new taxes must be taken seriously. And I say, 'Push him around? "(Trudeau) learned. You can't do that. "Other than he had a news conference that he had because he assumed I was in an airplane and I wasn't watching", Trump said.
The insults stemmed from a closing G7 press conference on Saturday in which Trudeau called USA steel and aluminum tariffs "insulting" and pledged to proceed with previously announced retaliatory tariffs.
"I think the first-hand interaction is likely to be a stronger factor than anything the president says", he said.
His earlier comments had followed Trump's own sharp words for Trudeau, whom the president called "dishonest and weak" and accused of making "false statements".
Trump has consistently railed against what he claims are unfair trade practices by some of America's biggest trade partners, including Canada - in particular Canada's supply management system, which levels tariffs of up to 300 per cent on imported dairy products.
"From the beginning we have said that our approach would be to work for the best possible outcome but to always be prepared for the worst, to have backup plans", she said.
If the US imposes a 25 per cent tariff on those exports, suddenly they don't make much economic sense, said Kristin Dziczek, vice president of industry, labour and economics at the Center for Automotive Research in Ann Arbor, Mich.
"I think as all of you know I believe it is always unwise to venture hypothetical responses to hypothetical actions", Freeland told reporters on Parliament Hill Tuesday.