Prime Minister Stephen Harper has shuffled two of his key ministers to fill the void left at the Department of Foreign Affairs by the departure last week of John Baird.

Harper this morning named Rob Nicholson as his new foreign affairs minister and Jason Kenney to replace Nicholson at National Defence. Kenney will keep his responsibilities as minister for multiculturalism.

Pierre Poilievre has been promoted to succeed Kenney as minister of employment and social development. He will retain his role as minister of state for democratic reform and also will take on Baird's responsibility for the National Capital Commission. Poilievre represents the same Ottawa-area region as Baird.

​In an interview with CBC News, Kenney said he's going to be focusing on Canada's military involvement in Iraq and the fight against ISIS, with a government-set six-month mission period set to end in early April.

"We're trying to be deliberate, intentional and prudent about this … I think our orientation on this is pretty clear, we want to play a significant role there," he said.

"The precise nature of our contribution in the past six months would not necessarily be the basis of an extension, we have to look at that very carefully, but our basic position is clear: we think Canada has a role to play in fighting this terrorist organization."

Kenney also said he will work on making as much progress as possible on major military procurement projects over the next eight to nine months, and will use his continuing role as minister for multiculturalism to reach out to new Canadians about serving in the military.

Mulcair: Nicholson can't reach out

The moves come nearly a week after Baird told the House of Commons that it was time for him to step down.

They were also announced the same day German Chancellor Angela Merkel makes an evening visit to Ottawa to talk about the conflict in Ukraine, one of the key files for Canada's Foreign Affairs Department.

In a statement issued by his office, Harper said, "The changes to the ministry announced today will help ensure that key portfolios continue to have the strong leadership required to advance Canadian priorities."

NDP Leader Tom Mulcair said Monday afternoon he was surprised by the appointments and took a shot at Nicholson's inability to speak French.

"[Nicholson has] never, ever wavered in any way, shape or form from strict Conservative Party dogma, and in a time like this, in a world we live in today, it is a bit surprising that we have someone who can't reach out more than he can," Mulcair said.

"Even his inability to say another word in Canada's second official language, you'd expect the person in charge of your diplomacy could speak a little bit of the language of diplomacy, which happens to be Canada's other official language, but he literally can't say a word, nor could his parliamentary secretary.

"You're shutting off a whole bunch of Canadians, and you're also showing a closed-mindedness to the rest of the world."

Mulcair also brought up the temporary foreign worker controversy, which happened during Kenney's time as employment and social development minister, and said Poilievre has an "abrasive character" that will put people off.

Kenney is PM's 4th defence minister

Mobile users, view a mobile-friendly graphic from The Canadian Press here.

Nicholson, 62, first elected as an MP in the riding of Niagara Falls in 1984, was re-elected in 1988 before losing in 1993 and 1997.

Re-elected in 2004 in the same riding, he has served as minister of democratic reform, minister of justice and was named minister of defence in July 2013, switching roles with Peter MacKay.

Jason Kenney, left, is Canada's new defence minister, while Rob Nicholson, centre, takes over Foreign Affairs following the resignation of John Baird. Pierre Poilievre, right, succeeds Kenney at Employment and Social Development. (Sean Kilpatrick/Fred Chartrand/Adrian Wyld/Canadian Press)

Kenney, 46, has held the riding of Calgary Southeast since 1997.

His past roles in cabinet include minister of citizenship, immigration and multiculturalism from October 2008 until July 2013, when he took over the employment and social development file.

He will be the fourth defence minister during Harper's time as prime minister, following Gordon O'Connor, MacKay and Nicholson.

Poilievre, 35, has handled some difficult files as a parliamentary secretary to the prime minister and minister of state for democratic reform during his more than 10 years as MP for Nepean-Carleton, but this is his first full-fledged cabinet role.

After the appointments were made official at Rideau Hall, Baird tweeted that all three were "great appointments" and called Nicholson a "smart, decent, experienced hand" at his former role.

PM made great appointments with <a href="https://twitter.com/HonRobNicholson">@HonRobNicholson</a>, <a href="https://twitter.com/kenneyjason">@kenneyjason</a> & <a href="https://twitter.com/PierrePoilievre">@PierrePoilievre</a>... —@Baird

"Great job for @kenneyjason at DND... look out ISIL!" he added.