Prompted by the resignation of former finance minister Mathias Cormann, Prime Minister Scott Morrison said stability and consistency were important in the uncertain time of the COVID-19 pandemic.

Mr Tehan takes on the role, which includes tourism and and investment, at a time when trade tensions with China are causing significant pain for exporters.

In other news: Health Minister urges Canberrans not to travel to Sydney

Formerly an official at the Department of Foreign Affairs and Trade, Mr Tehan is from the regional Victorian electorate of Wannon and Mr Morrison said he has "a keen sense of the particular interests of regional and rural Australia in open, rules-based trading systems".

Aged care will be elevated into cabinet, with Health Minister Greg Hunt to represent that portfolio at the table, but junior minister Richard Colbeck will retain responsibilities in the area, despite his oft criticised performance in the role.

Mr Morrison also batted away the suggestion it was a demotion for Senator Colbeck, saying the change was only about ensuring aged care was represented in cabinet.

"That is important that we elevate aged care into the cabinet because of the seriousness of this issue, the size and scale of the reform program that will need to be implemented post the royal commission report," he said.

"So I'm preparing for that by ensuring that the aged care portfolio is held at the highest level it can be."

Despite rumours of wider changes, there has been no changes to the Defence, Foreign Affairs, Home Affairs, Treasury, Finance, and employment and skills.

There have been no changes among the Nationals members of the cabinet, which stays at 22 members.

Mr Morrison said only modest changes were needed as his team of ministers was doing an "outstanding job".

Simon Birmingham had already been given the finance portfolio after Senator Cormann's resignation, required trade to be assigned elsewhere.

Alan Tudge will take on the Education portfolio from Mr Tehan, and will become Minister for Education and Youth.

Asked why Mr Tudge had been promoted despite the revelations from the ABC's Four Corners program that he had an affair with his staffer in recent years, Mr Morrison said those issues were in the past.

"Alan's decisions in his own personal life, he has taken full personal responsibility for, and no-one has paid a greater price for those things than his family and those that they affected, and himself," Mr Morrison said.

"What has impressed me about Alan is he's dealt with these issues honestly."

David Coleman is set to return from a long period of leave and take on the role of assisting the prime minister on mental health and suicide prevention.

Jane Hume has been promoted to a ministerial role, taking on digital economy responsibilities as well as superannuation and financial services.

Assistant Treasurer Michael Sukkar, who has responsibility for housing, will also become part of the Social Services department as Minister for Homelessness, Social and Community Housing, a move Mr Morrison said would bring all types of housing under the one minister.

Ally to Mr Morrison Alex Hawke has been promoted to Immigration Minister, including responsibility for citizenchip and migration.

ACT Senator Zed Seselja has been promoted from assistant minister to minister for the first time, taking on International Development and the Pacific.

"Zed has a great experience in the parliament, he's served in a number of assistant minister roles," Mr Morrison said.

"He will also play a key role in ensuring that we roll out the vaccine in our Pacific family into the new year.

"Being an ACT senator situates him also very well with all the embassies and missions which are here in the ACT, enabling him to work well with those development partners as part of those roles."

Ben Morton, who has been acting as assistant minister responsible for the public service has taken on that role formally, and will also take on electoral matters.

Queensland Senator Amanda Stoker has been promoted to assistant minister to the attorney-general, and West Australian MP Andrew Hastie has been promoted to assistant minister for Defence.

Mr Morrison said it was "rubbish" to suggest Mr Hastie had been rewarded for taking a vocal stand against China.