The UK's withdrawal from an arrangement allowing other countries to fish in British waters is unhelpful, the Irish Government has said.
Ministers will trigger exit from the London Fisheries Convention, signed in 1964 before joining the EU, to start the two-year process to leave the agreement.
The convention allows vessels from France, Belgium, Germany, Ireland and the Netherlands to fish within six and 12 nautical miles of the UK's coastline.
Irish Agriculture, Food and Marine Minister Michael Creed said: "Today's announcement by the UK Government is unwelcome and unhelpful.
"It is a part of Brexit and will be considered by the EU 27 member states and the (Michel) Barnier team when the negotiations commence."
The Convention grants rights to neighbouring countries to fish in each other's fishing zones based on historic fishing activity.
The Irish fishing fleet has access to parts of the UK six to 12-mile zone, as has the UK fleet to parts of the Irish zone.
These access rights were incorporated into the EU Common Fisheries Policy.
Mr Creed added: "Brexit poses very serious challenges to the seafood sector and this announcement will form part of the negotiations."
Sean O'Donoghue, chief executive of the Killybegs Fishermen's Organisation, a large fish producers' group based on Ireland's west coast, said it is an aggressive measure by the British.
"We are not surprised, we did expect it," he said.
"The access for us is huge but the access between six and 12 is not our greatest priority, our access is between 12-mile limit and 200 UK-wide limit.
"That is the important one."
The EU Common Fisheries Policy allows all European countries access between 12 and 200 nautical miles of the UK and sets quotas for how much fish nations can catch.
