The DUP is threatening to launch legal action against the British Government over the legality of the Northern Ireland Protocol.
Arlene Foster, Jeffrey Donaldson and Sammy Wilson say the Brexit settlement for the North goes against the Act of Union.
Later today the House of Commons will debate the party's petition, demanding Britain lift customs and agriculture checks on goods crossing the Irish Sea.
However Fianna Fáil's Brexit spokesperson Lisa Chambers says Unionists should give the system more time to work out any early kinks.
Tinahely Scoops Best Actress Award on All Ireland Stage
Wicklow Left Heartbroken As Dublin Do Just Enough To Escape Aughrim With Narrow Win
Young Arklow Tennis Talent Secures Sponsorship for Elite Training in Mallorca
Revised Plan For Boghall Road Site Could Create 30 Jobs In Wickow
Wicklow Reach For The Stars Dreaming Of Dubs Upset