By Jayne McCormack, BBC News NI Political Correspondent
Sir Keir Starmer is making his first visit to Northern Ireland since becoming prime minister.
The overnight visit will see the Labour leader continue his tour of the UK after he travelled to Scotland earlier on Sunday.
He is expected to visit Stormont on Monday to meet First Minister Michelle O’Neill and Deputy First Minister Emma Little-Pengelly.
Ahead of the meetings, Sir Keir said “stability and certainty” would be at the centre of what his government does for Northern Ireland.
‘Party of the Good Friday Agreement’
“We are the party of the Good Friday Agreement, and the stability it has brought,” he said.
“Together, as we take the steps towards a decade of national renewal, we will harness Northern Ireland’s vast economic strengths – rebuilding strong public services and generating real and tangible economic growth for working people.
“We must turn the page and secure investment, prosperity, and stability for future generations to come.”
The new Secretary of State Hilary Benn arrived in Northern Ireland on Saturday and held talks with most of the main political parties.
On Sunday, he visited businesses in Belfast city centre, where he told reporters that Casement Park “has to be built”, but urged people to bear with him while he ploughs through the issues.
Labour has been urged by political parties and sporting organisations to commit funding to ensure the stadium can be redeveloped in time for Euro 2028.
Mr Benn said he wouldn’t be pressured into saying Casement Park will be built in time for the Euros in 2028 but said “as soon as I’m in a position to make that decision I will”.
He previously said a Labour government could not write a “blank cheque” for the redevelopment.
Sir Keir is also likely to be asked about committing to funding when he meets the political parties at Stormont on Monday.
He will meet the first and deputy first ministers to discuss a range of issues and areas of shared co-operation, agreed during their call on the prime minister’s first day in office.
He will then meet other political leaders in the executive and opposition parties at Stormont.
The new UK prime minister has also got plans to meet politicians in the Republic of Ireland.
Taoiseach (Irish prime minister) Simon Harris and Sir Keir are to meet later this month.
On 5 July, the taoiseach spoke to the prime minister by phone.
Mr Harris told his Fine Gael party in a private meeting on Wednesday that he was making plans to seek an early engagement with the new UK government.
During the call on Friday, Mr Harris congratulated Sir Keir on his new role and his party’s victory in the election.
The taoiseach said he “looked forward to having a close and constructive working relationship”.
Mr Harris accepted the prime minister’s invitation to visit Downing Street on 17 July.
Analysis: Jayne McCormack, political correspondent
With Friday’s electric set of election results just about sinking in for Sir Keir Starmer, there’s no time to waste.
The last time the Labour leader went to Stormont he promised to repeal the controversial legacy act if his party took power.
On that, the first and deputy first ministers and other parties have already held talks with Hilary Benn, the sixth Secretary of State in five years.
From the Tories, Labour has also inherited the question of cash for Casement Park’s redevelopment.
It previously said it couldn’t write a blank cheque, but whether Sir Keir is prepared to hand over the funding as prime minister will come up in many of his conversations tomorrow.