Fine Gael says the British government's plans to scrap parts of the Northern Ireland Protocol will be a 'breach of international law'.
Boris Johnson's proposals to be published in Parliament today are set to include powers to remove all customs checks between Britain and the North.
They will also allow businesses in the North to decide whether to follow British or EU regulations.
Fine Gael's European Affairs spokesperson Neale Richmond says this will put the Good Friday Agreement at risk.
Meanwhile, the Irish Farmers Association President says it's "vital" any change to the protocol doesn't interfere in trade between the North and the Republic.