In farewell statements to the House of Commons, former foreign affairs minister Stéphane Dion and former immigration minister John McCallum told MPs they are leaving Ottawa to continue serving the public as the respective ambassadors in Europe and China.

Dion said he had accepted Prime Minister Justin Trudeau's offer to become Canada's "senior diplomat to Europe" by taking on the dual role of ambassador to the European Union and Germany. MP John McCallum also said goodbye to the House as he readies himself to become Canada's ambassador to China.

Both were shuffled out of the federal cabinet earlier this month.

Dion said that after the cabinet shuffle he had to consider whether to return to teaching or to remain in public service. Thanking the University of Montreal for giving him a tempting offer, Dion said he had instead decided to join the diplomatic corps.

"I will do my part to strengthen Canada's relationship with Europe. It will be an honour to join the Canadian diplomatic corps," Dion said.

McCallum's early days in China are expected to be dominated by preliminary talks that the Liberal government expects to eventually deliver a free trade deal between the two countries.

"As I stand in this place for the last time, I naturally do with mixed emotions," McCallum told his colleagues, adding that the more he thought about it, "this China assignment is the perfect job for me and I am grateful to the prime minister for his confidence."

McCallum said the immigration portfolio "is in good hands" because new minister Ahmed Hussen is a "quick study" and has a "big heart."

Regarding his most memorable moments in the House, McCallum spoke particularly of nominating the late South African president Nelson Mandela for honorary Canadian citizenship.

McCallum said the work he did over the last year to bring nearly 40,000 Syrian refugees to Canada was another highlight of his political career, especially since it was done when so many other countries were "closing their doors" to refugees, he said.

Looking to China, McCallum said he would work very hard as ambassador to help vulnerable Canadians in China who need consular assistance.

In his parting words to MPs he said, "Have the capacity to govern our country well, and have the wisdom to make Canada even better in years to come."

Dion off to Europe

Dion, most recently Canada's foreign affairs minister and a one-time Liberal leader, was replaced at Foreign Affairs by Chrystia Freeland, who had held the international trade portfolio.

Since the Jan. 10 cabinet shuffle, Dion had been tight-lipped about his future, but McCallum seemed to let the news slip out in his farewell speech, saying he was happy he could look forward to continuing to work with Dion in the world of diplomacy, prompting a smiling Dion to wave his hands in denial.

Dion entered politics at the request of former prime minister Jean Chrétien on Jan. 25, 1996, and went on to write the Clarity Act establishing rules and conditions for any future attempts at secession by Quebec.

The Supreme Court backed his position — that Quebec could not unilaterally secede from Canada — with the bill passing into law in 2000. Dion's work on national unity was lauded by both sides of the House.

Trudeau described Dion as a mentor and a friend who has always been a "great defender of the Canadian project."

"Thanks to their efforts, Canada is a more united country," Trudeau said. "I know I speak for everyone in this House when I say these members will be missed."

Interim Conservative Leader Rona Ambrose left the goodbye remarks on McCallum to Tory immigration critic Michelle Rempel.

Speaking to Dion, Ambrose said she was always impressed by Dion's "steadfast" adherence to his principles and admired his work on Canadian unity.

Economist goes to China

McCallum was first elected to the House of Commons in 2000 and held the defence, veterans affairs and national revenue portfolios under Prime Minister Paul Martin. He was appointed immigration minister by Trudeau.

A former chief economist of the Royal Bank of Canada, McCallum also worked as a professor of economics at McGill University, Simon Fraser University, the University of Manitoba and the University of Quebec in Montreal.

In announcing his departure from cabinet, Trudeau applauded McCallum's work in helping to bring in nearly 40,000 Syrian refugees to Canada.

"The Canada-China relationship will be well-served by such a strong presence from our government," Trudeau said in a statement when he announced McCallum's new job.

Rempel said Canada is a compassionate country and expresses that compassion through its immigration policy, "and I think in that the member from Markham-Thornhill should be remembered by his actions."

NDP Leader Tom Mulcair said McCallum was an excellent economist and a hard-working MP who was always willing to reach across party lines to work together.

"He is a man of strong principle who has always served the public first and foremost," Mulcair said.