Regional lawmaker Paul Givan will serve as Northern Ireland's next first minister when incumbent Arlene Foster steps down, the Democratic Unionist Party said on Tuesday.

New DUP leader Edwin Poots announced on Twitter that the 39-year-old hardline unionist will take on the post after Foster was ousted in a party coup over her handling of Brexit.

At Northern Ireland's regional government at Stormont, Poots said Givan and other new ministers will take up their posts on Monday, cutting short Foster's plan to step down "at the end of June".

"There is a huge responsibility that comes with this position, particularly in serving the people of Northern Ireland," he said.

Givan is a lawmaker in Stormont, and is considered a hardcore pro-UK unionist with stringent conservative views on social issues.

He is also a fiercely loyal follower of Poots, the newly-elected DUP leader who has pledged to wage a war against new post-Brexit arrangements for Northern Ireland.

Foster, 50, was ousted from her position at the top of the DUP -- Northern Ireland's largest unionist party -- after a new post-Brexit "protocol" came into effect in January.

Many unionists feel the new trading arrangements have warped the place of Northern Ireland in the United Kingdom, and while the DUP has strongly opposed it they have been powerless to intervene.

Foster was considered by many in the DUP as a more compromising leader and it is expected Givan will escalate the battle against the "protocol" under the guidance of Poots.

Paul Givan, left, has been tapped to be Northern Ireland's next first minister by DUP leader Edwin Poots, right
Paul Givan, left, has been tapped to be Northern Ireland's next first minister by DUP leader Edwin Poots, right AFP / PAUL FAITH

At 18 years old, Givan's first job was as a part-time assistant in Poots' constituency and Stormont offices, according to The Belfast Telegraph.

He later worked as a special adviser to Poots before becoming a regional legislator for the Lagan Valley constituency in 2010 and was minister for communities from 2016 to 2017.

Like Poots, Givan is reported to be a creationist Christian with beliefs that the Earth was made by God, in a party with fundamentalist roots and deeply conservative views on issues such as same-sex marriage and abortion.

In 2007 he spearheaded a deeply controversial local government motion that asked school science departments in the city of Lisburn to explain plans to teach alternatives to the theory of evolution.

In 2015 Givan also put forward proposals for a controversial "conscience clause" he said was needed "to stop the civil persecution of people of faith".

Opponents claimed it was a fig leaf designed to allow discrimination against gay people in Northern Ireland.

"When I walk into Stormont I don't leave my values at the door," Givan told The Belfast Telegraph in 2014.

"My religious beliefs seek to influence every aspect of my life from trying to be a good dad, husband, citizen and politician."

Givan also had a prominent role in the collapse of Northern Ireland's power-sharing executive from 2017 to 2020.

His decision to slash funding to an Irish language scheme has been described by opponents as "the straw that broke the camel's back", prompting the three-year hiatus of regional government.