The Northern Ireland Protocol has cast a “long shadow” over political arrangements at Stormont, DUP leader Sir Jeffrey Donaldson has said.

Sir Jeffrey told a plenary meeting of the British-Irish Parliamentary Assembly (Bipa) that the Stormont Executive would only be restored when issues surrounding the protocol were resolved.

However, Sinn Fein MP John Finucane told the meeting that the protocol was a result of the DUP championing of the “hardest possible Brexit”.

The protocol prevented a hard border on the island of Ireland after Brexit, but is deeply unpopular with unionists because it introduced new trade barriers in the Irish Sea between Northern Ireland and the rest of the UK.

While the EU has given concessions on its operation, notably to ease the flow of medicines, these have not satisfied many who oppose it.

Northern Ireland’s powersharing Executive collapsed earlier this month when the DUP’s Paul Givan resigned as first minister in protest at the protocol.

His party leader told the Bipa meeting: “Those who claim that the Northern Ireland Protocol is designed to protect the Good Friday Agreement and the political institutions that were created by it surely must now recognise that the three sets of relationships covered by the agreement have been damaged since the protocol was implemented.

“The continued imposition of the protocol upon Northern Ireland has cast its long shadow over our political arrangements at Stormont, as well as on a north-south and east-west basis and the everyday lives of our people.

“The genuine objections to it cannot be wished away, nor simply ignored.”

Sir Jeffrey added: “Only by recognising the fundamental flaws of the protocol can lasting replacement arrangements, which command the necessary support be put in place.

The long shadow of the Irish Sea border must be removed from our politics. It is holding us back

“As the leader of Northern Ireland’s largest party, I must stress that the problems of the protocol are not confined to unionists, but affect the everyday lives and livelihoods of everyone in Northern Ireland.

“The long shadow of the Irish Sea border must be removed from our politics. It is holding us back.”

Sinn Fein MLA John O’Dowd asked the DUP leader if his party would return to the Executive if it was no longer the largest party following Stormont elections on May 5.

Sir Jeffrey said: “I will gladly go back into an Executive if I get respect and I get action on the issues that matter to me.

“I am a democrat, I will respect the outcome of elections, but what I am not prepared to do is bury my head in the sand, pretend these problems aren’t there.

“When this is sorted out and when we have agreement, you will get a restored Executive.”

Mr Finucane told the meeting: “The DUP boycott of the Executive and the North South Ministerial Council amounts to an assault on the Good Friday Agreement itself.

“It is destabilising for politics and for society and it is a direct result of the political fallout between the Tories and the DUP.

“Both championed the hardest possible Brexit yet take no responsibility for its consequences.”

The British-Irish Parliamentary Assembly meets twice a year to provide a forum for parliamentarians across the UK, Ireland and the Crown dependencies to discuss issues of mutual interest.