Election 2024: DUP will shortly announce election candidate for Lagan Valley, says Campbell

The Alliance Party has also said a decision will be made within days on whether leader Naomi Long would challenge DUP interim leader Gavin Robinson in East Belfast.

The Northern Ireland parties are gearing up for a poll during the school holidays in the region after the surprise announcement by Prime Minister Rishi Sunak that the General Election will take place on July 4.

Sinn Fein has emerged as the largest party in the Assembly and local council elections in the last two years and will be hoping to repeat that success again.

The republican party won seven seats at the last General Election, compared with eight for the DUP, the largest unionist party.

However, Sinn Fein's North Belfast MP John Finucane said the party was concentrating on its message, rather than political rivals.

He told the BBC Good Morning Ulster programme: "First and foremost we want to retain the seven seats that we have and in other constituencies we want to grow our vote.

"We want to increase our mandate."

Mr Finucane said one of his party's main election themes would be the need to address the underfunding of public services in Northern Ireland.

He said: "We will be consistent in our calls to highlight the underfunding that we have faced which has completely restricted our ability to have proper public services.

"We will continue that engagement with whoever leads the next British Government."

Mr Finucane also said his party would not be changing its abstentionist policy which sees it MPs not taking their seats at Westminster.

The DUP's East Londonderry MP Mr Campbell confirmed he would be standing again but said the party's selection processes across all constituencies was not completed.

The party faces a choice over which candidate to run in Lagan Valley after former party leader and long-time MP Donaldson was charged with a series of historical sexual offences - charges he denies. He will not seek re-election.

Two of the unionist party's most high profile MLAs - deputy First Minister Emma Little-Pengelly and Education Minister Paul Givan - represent the constituency.

It is anticipated that the DUP will face a stiff challenge from the Alliance Party's Sorcha Eastwood in Lagan Valley.

Mr Campbell said: "We haven't completed our selection of candidates of yet.

"We will be doing that in the next few days and Lagan Valley will be included in that."

He added: "We have a number of very good candidates and I think our party leader (Mr Robinson) would be describing all of them as very suitably qualified."

The cross-community Alliance Party's North Down MP Stephen Farry said the election represented the opportunity for change.

He added: "Here in Northern Ireland we have a huge opportunity to send a different balance of representation to Westminster."

He said that a successful election for Alliance would send the message that Northern Ireland is "moving away from the politics of green versus orange".

Mr Farry said the party would make clear in the coming days if leader Ms Long would be challenging Mr Robinson in East Belfast, a seat she previously held.

Ulster Unionist leader Doug Beattie confirmed he would run a candidate in all 18 Northern Ireland constituencies and was not considering pacts with other unionist parties.

He added: "We speak to other unionist parties on a variety of issues but I have also made it clear I am not somebody who does pacts work."

Mr Beattie also confirmed that he would be writing to Stormont's speaker to begin the process of Robin Swann being replaced as health minister by Mike Nesbitt.

Mr Swann will contest the South Antrim seat in the Westminster poll where he hopes to topple the DUP's Paul Girvan.

The SDLP is hoping to hold onto its seats in Foyle and South Belfast.

Party leader Colum Eastwood conceded he would face a "tough fight" from Sinn Fein in Foyle.

He added: "The real fight here is to get rid of the Tories.

"We have had 14 years of these people destroying our economy, doing Brexit, bringing in the Legacy Act, stripping our public services of funding.

"Now there is an opportunity to get rid of them."