DUP leader Sir Jeffrey Donaldson has urged the quick resolution to unionist issues with the Northern Ireland Protocol.

Sir Jeffrey held talks with the Irish premier Micheal Martin in Dublin on Friday, which were described as “frank and open”.

The Lagan Valley MP said he warned the Taoiseach that unionists “cannot be expected to work as normal” with Ireland when Northern Ireland’s relationship with the rest of the UK is “being harmed on a daily basis” by the protocol.

The Taoiseach, speaking separately, said he acknowledged “the concerns of the unionist community are sincere”.

“But I indicated as well that the mechanisms are there in the UK-EU trade agreement to resolve these issues and the issues around the protocol,” he said.

“Our sense has been that the EU Commission has been flexible and ready to respond to the situation.

“We do need to see similar flexibility from the UK Government side.”

Unionists are strongly opposed to the impact on the additional checks under the protocol on trade between Northern Ireland and Great Britain, arguing it places a border down the Irish Sea.

Legal action has been taken against the protocol while loyalists have been holding a series of demonstrations against the post-Brexit arrangements.

Sir Jeffrey said he told the Taoiseach that unionist concerns over the protocol are growing, and of the potential for it to cause further political harm later in the year.

He said the harm to the east/west relationship may have consequences for the north/south relationship in Ireland.

Unionists cannot in any circumstances support such a situation and therefore the Irish Sea border needs to be removed

“Unionists cannot reasonably be expected to work as normal on a north/south basis when our relationship with the rest of the United Kingdom is being harmed on a daily basis by this protocol,” he said.

“That is simply the reality of the political situation that we face.

“I don’t want to see a political crisis in Northern Ireland, I don’t want to see the political institutions being harmed, I want to see a Northern Ireland where we move towards a more united community, but the protocol is harming our capacity to build that united community.”

Sir Jeffrey said issues around the protocol need to be addressed, and quickly.

“We need to remove the border that has developed between Northern Ireland and Great Britain in trading terms, we need to recognise that for unionists that cuts across the very Act of Union itself, which is the very fundamental building block of our relationship with the rest of the United Kingdom,” he said.

“Unionists cannot in any circumstances support such a situation and therefore the Irish Sea border needs to be removed, and we need to find practical solutions that will enable trade to return to normality between Great Britain and Northern Ireland, and at the same time put in place measures that protect the integrity of the EU single market.

“Those two situations are not mutually exclusive.”