Irish fisheries organisations are seeking legal advice about overturning a 2013 agreement between Ireland and the UK that includes Rockall in Britain’s exclusive economic zone.

Chief executive of the Irish Fish Producers Organisation (IFPO) Francis O’Donnell said the agreement effectively conceded the rock and its surrounding fisheries area in the North Atlantic to the UK.

Mr O’Donnell believes that after Brexit “we will be losing a fishing zone we have fished for the last 200 years”.

But the Department of Foreign Affairs has insisted the agreement does not affect the entitlement of the Irish fisheries sector to work at the outcrop.

The bilateral agreement established a single maritime boundary between the exclusive economic zones and continental shelves of Ireland and the UK, putting Rockall on the UK side of the boundary.

It was signed by then tánaiste Eamon Gilmore, who said at the time the agreement established “a clear framework for the government’s efforts to encourage and facilitate the sustainable development of our marine resources in the seafood, oil and gas, renewable energy and biotechnology sectors”.

EU waters Ireland does not recognise the claim over the disputed territory 386km from the Scottish mainland but has never sought to claim sovereignty itself and, like Iceland and Denmark, considers it part of EU waters.

Contacts between Irish and Scottish officials have been stepped up to “de-escalate” the row.

A spokesman for Minister for Foreign Affairs Simon Coveney said on Friday that “Rockall is in the UK economic zone, that’s not disputed. But it remains [in] EU fishing grounds”.

The spokesman stressed that “the issue with Rockall isn’t economic zones. It’s whether the Scottish can claim it as sovereign territory and draw a fishing boundary around it.”

“We say that’s not the case and a sea stack can’t be tested in this way,” he added.

But Mr O’Donnell said “it doesn’t matter how anyone dresses this up”, it is a territorial issue for Irish fisheries, and Rockall “has effectively been handed over to the UK”.

He said “if the Government was strategic it would have registered a claim for Rockall but we’ve never been strategic about natural resources”.

Reciprocal rights Sinn Féin senator Pádraig Mac Lochlainn, who raised the issue in the Seanad, asked whether the threat this month from Scotland was linked to controversial legislation restoring reciprocal fishing rights to fishermen from Northern Ireland in the Republic’s waters.

He said the legislation was pushed through the Oireachtas on the basis of building good relationships between the Republic and the UK for access to fishing waters after Brexit.

“Everybody was puzzled as to why a usually prudent Scottish National Party government in Scotland is taking these measures. It turns out they are based on a 2013 agreement” that he said was done without Iceland’s approval.

In effect, he said, “government representatives vindicated the British claim to the fisheries around Rockall and gave the Scottish government the legal basis to threaten to remove Irish boats”.

He called on Minister for the Marine Michael Creed to come into the Seanad and clarify when that correspondence started.