As president-elect Donald Trump prepares to assume office, his cabinet nominees are still working their way through the congressional approval process — with the first confirmations not expected until Friday at the earliest.

At least five of those appointments will be critical for Canada. Trump's cabinet picks for the foreign affairs, trade, environment, homeland security and energy files are likely to test their Canadian counterparts as the U.S. embarks on a change in policy across government over the next four years.

Here are five of the U.S. ministers to watch along with their Canadian counterparts.

Foreign affairs

Rex Tillerson, the U.S. nominee for secretary of state, left, and Canada's Minister of Foreign Affairs Chrystia Freeland. (Canadian Press)

Trump's pick for secretary of state is Rex Tillerson. He joined Exxon as an engineer in 1975, and by 2006 had risen to become chairman and CEO of the board of the Exxon Mobil Corp.

If confirmed, he'll be dealing with Canada's new Foreign Affairs Minister Chrystia Freeland, who has also retained primary responsibility for the Canada-U.S. trade file after being moved into her new role from the Ministry of International Trade.

Both will be faced with Vladimir Putin and Russia. Tillerson has a good relationship with Putin and a long history of working with Russia. Freeland, however, is a critic of Russia who has been banned from entering that country. Their very different relationships will likely complicate joint security and economic projects.

If Trump follows through on his pledge to tear up NAFTA, Freeland would have to deal with the renegotiation.

Trade

Robert Lighthizer, Trump's pick for U.S. trade representative, left, and Canada's Minister of International trade François-Philippe Champagne. (GreatAgain.gov/Canadian Press)

Trump's nominee for U.S. trade representative is Robert Lighthizer, who served under former president Ronald Reagan.

As a lawyer, Lighthizer developed a reputation for accusing some of the U.S.'s trading partners of subsidizing their exports while making it harder for the U.S. to import goods into foreign markets. His selection is seen as proof positive that Trump intends to make good on his promise to get tough with trading partners perceived to be giving the U.S. a raw deal, namely Mexico and China.

The trade representative may not be as directly influential as in previous administrations, however. Trump has created a new White House National Trade Council and has named economic adviser Peter Navarro to head it. And most significantly, Trump's nominee for commerce secretary, Wilbur Ross, has been the strongest voice articulating Trump's trade policy so far.

On paper, Canada's new minister of international trade, François-Philippe Champagne, appears to be Lighthizer's counterpart. But he won't be the one dealing with the Americans.

When Prime Minister Justin Trudeau shuffled his cabinet, he explicitly left responsibility for Canada's trade relationship with the U.S. with Freeland, the former trade minister, who had been chairing the cabinet committee on Canada-U.S. relations and leading talks on key irritants like the contentious softwood lumber file.

The much-anticipated renegotiation of NAFTA will be one of Freeland's top priorities.

Homeland security

Retired general John Kelly, the nominee for U.S. secretary of homeland security, left, and Canada's Minister of Public Safety and Emergency Preparedness Ralph Goodale. (Canadian Press)

Retired marine general John Kelly is Trump's nominee for the secretary of homeland security. Kelly has a long military history, having enlisted in the Marine Corps in 1970.

Kelly will be charged with rolling out some of Trump's more controversial campaign promises: extensive vetting for all immigrants, finding and deporting illegal immigrants, securing the border with Mexico and aiding in the fight against international human and drug trafficking into the U.S.

He'll be dealing with Liberal veteran Ralph Goodale, Canada's minister of public security. Their relationship will depend on how Trump will proceed with promises such as building a wall on the Mexican border, expelling millions of undocumented migrants and cracking down on global terrorism.

Environment

Scott Pruitt, Trump's nominee for the administrator of the Environmental Protection Agency, left, and Canada's Minister of Environment and Climate Change Catherine McKenna. (Canadian Press)

Trump's pick to head the U.S. Environmental Protection Agency is Scott Pruitt. The Oklahoma attorney general is a climate change skeptic and a close ally of the fossil fuel industry who has opposed the EPA directly in his current job.

Environment Minister Catherine McKenna has championed the Paris agreement on climate change and is forging ahead with a number of environmental measures, including a carbon tax plan with the provinces.

As Canada strives to meet its commitments agreed to in Paris, it will be losing an ally in its neighbour to the south. President Barack Obama was a staunch proponent of the deal, while Trump has in the past called climate change a "hoax" — although he has more recently said he has an "open mind" about the accord.

Energy and natural resources

Former governor of Texas, Rick Perry, Trump's nominee for secretary of energy, left, and Canada's Minister of Natural Resources James Carr. (Canadian Press)

Former Texas governor Rick Perry is Trump's pick for U.S. energy secretary, which was initially seen as an odd choice considering Perry once said he wanted to eliminate the department — although he climbed down from that position when answering questions before his Senate confirmation hearing this week.

As governor of Texas from 2000 to 2015, Perry developed a reputation for being an enthusiastic supporter of the resource industry, which will have him in good stead with Canada's Natural Resources Minister Jim Carr.

Carr needs to get more pipelines built, which could be made easier if Perry is able to help reverse Obama's decision to reject the proposed Keystone XL pipeline, which would bring oil from Alberta across the border into the U.S.

Correction: An earlier version of this story said U.S. trade representative Robert Lighthizer's counterpart would be Canada's international trade minister, François-Philippe Champagne, on issues such as softwood lumber. In fact, Foreign Affairs Minister Chrystia Freeland is responsible for trade relations with the U.S.