Until now, Senator Seselja had been an assistant minister, most recently for Finance, Charities and Electoral Matters.

"Zed has a great experience in the parliament, he's served in a number of assistant minister roles," Prime Minister Scott Morrison said on Friday.

"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."

Mr Morrison said Australia's relationship with countries across the Pacific was critical to the government, and he had spoken to Fijian Prime Minister Frank Bainimarama in recent days to offer support as the country is hit by Cyclone Yasa.

"Our step up to our Pacific family is felt very deeply by our Pacific family and friends, and this is a matter that is critically important to the government," Mr Morrison said

Senator Seselja is one of two promotions to minister in the Senate, with Jane Hume also promoted to minister.

"It is an honour to be appointed Minister for International Development and the Pacific by the Prime Minister," Senator Seselja said.

"I look forward to working with the Prime Minister and Minister for Foreign Affairs Marise Payne to deliver the Australian government's priorities in this important portfolio."

West Australian MP Ben Morton will take on Senator Seselja's responsibilities for electoral matters.

Elected to the Senate in 2013 after nine years in the ACT Legislative Assembly, Senator Seselja has already been an assistant minister for a variety of portfolios.

His assistant portfolios includes for social services and multicultural affairs; science, jobs and innovation; and treasury and finance.

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