Donegal TD Pat the Cope Gallagher has said the decision by UK government to withdraw from the London Fisheries Convention is deeply disappointing.
The move would see trawlers from the Republic of Ireland unable to fish within 12 nautical miles of the UK coastline.
Deputy Gallagher, the Fianna Fáil Spokesperson on Fisheries, said the Irish government must insist that the issue is discussed as part of the overall trade negotiations.
"It must be remembered that the U.K. exports 62% of its fish catch to the remaining 27 member states, so the trade element is a crucial component of negotiations on fisheries,” he said.
"When Brexit Negotiator, Michel Barnier visited Dublin a number of months ago, I raised this issue with him directly, and I found him to be very receptive to my concerns on post-Brexit fisheries issues.
"This convention pre-dates the entry of both Ireland and the UK into the European Economic Community, and provided all signatory counties with reciprocal fishing rights in each other's waters.
"It's clear that the UK government's commitment to a hard Brexit now extends to ripping up any deal with neighbouring countries irrespective of the benefits.”
Minister For Agriculture, Food And The Marine, Michael Creed, said move was “unhelpful”.
"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 MSs and the Barnier team when the negotiations commence,” he said.
“The announcement will have no immediate effect as the withdrawal process from the convention will take two years and will form part of the Brexit negotiations.
“The convention grants rights to neighbouring countries to fish in each other's 6 to 12 miles fishing zones based on historic fishing activity. The Irish fishing fleet has access to parts of the UK 6-12 mile zone as has the UK fleet to parts of the Irish zone. These access rights were incorporated into the EU Common Fisheries Policy when we joined the EU.
“The threats posed by Brexit to the Irish fishing industry was discussed last Thursday with the Irish industry at a session of the SeaFest Conference in Galway. Brexit poses very serious challenges to the seafood sector and this announcement will form part of the negotiations."