Foreign Affairs Minister Maxime Bernier's diplomatic gaffe in Afghanistan suggests he doesn't have the capacity to handle the portfolio and should be replaced, Liberal critic Bob Rae said Thursday.

Rae, the party's foreign affairs critic, held a news conference in Ottawa to denounce Bernier's blunder and question his record as minister.

"To make a mistake of this character at this stage of the proceedings in Afghanistan after we've been there so long … is a very big mistake indeed," said Rae.

"I think it poses questions about Mr. Bernier's capacity to do what needs to be done."

Liberal Leader Stéphane Dion has called for Bernier's dismissal, saying he lacks the experience to run such a high-profile portfolio.

The NDP on Thursday tabled a motion before the parliamentary Foreign Affairs committee asking it to summon the minister to explain his comments. The committee will vote on the motion at the end of the month.

The issue arose Monday after Bernier, who was visiting Afghanistan, told reporters that Afghan President Hamid Karzai should replace Kandahar Gov. Assadullah Khalid.

Bernier was forced to clarify the comments hours later, saying he was only expressing the same concerns that the United Nations has about governance in Afghanistan and the need to fight corruption.

Prime Minister Stephen Harper defended Bernier, saying he had "very quickly corrected the misimpression" left by his comments.

But Rae, who grilled Bernier Wednesday during question period, said he believed Bernier's comments have damaged Canada's and NATO's efforts in Afghanistan.

"What he has said has had a negative effect on our efforts in Afghanistan. The deed is done and that's the problem that we have," he said.

Rae acknowledged there are "serious issues with respect to governance and … with the governor of Kandahar," but that the issue could be raised through diplomatic channels.

"Bernier's way to carrying on has been ineffective," he said.

With files from the Canadian Press