Tánaiste Leo Varakdar has warned political leaders not to enter any agreements with the British government until they are confident it will keep its promises.
Mr Varadkar was speaking after Dominic Cummings indicated the British government never planned to stick to the Brexit deal.
UK prime minister Boris Johnson’s former adviser claimed the UK government always intended to “ditch” the Northern Ireland Protocol.
Mr Cummings said in a series of tweets that he had planned to get Mr Johnson to “ditch the bits we didn’t like” after beating Labour in the 2019 general election.
The Tánaiste told RTÉ's Morning Ireland: “I saw those comments; I hope Dominic Cummings is speaking for himself and not for the British government.
“But those comments are very alarming because that would indicate that this is a government, an administration, that acted in bad faith and that message needs to be heard around the world.
“If the British government doesn’t honour its agreements, it doesn’t adhere to treaties it signs, that must apply to everyone else too.
“At the moment, they’re going around the world, they’re trying to negotiate new trade agreements… Surely the message must go out to all countries around the world that this is a British government that doesn’t necessarily keep its word and doesn’t necessarily honour the agreements it makes.
“And you shouldn’t make any agreements with them until such time as you’re confident that they keep their promises, and honour things, for example, like the protocol.”
It comes as the EU is set to outline a range of proposals aimed at resolving the political stand-off over the protocol.
📍Vice-President @MarosSefcovic will hold a press conference today on the Protocol on Ireland / Northern Ireland at approximately 18:30 CET @EU_Commission.
You can watch it live here: https://t.co/To28pGgcPn pic.twitter.com/cQemfbNeJI— Daniel Ferrie 🇪🇺 (@DanielFerrie) October 13, 2021
European Commission vice-president Maros Sefcovic has promised the measures will be “very far-reaching” and address issues over the movement of agri-food goods and medicines across the Irish Sea.
The proposals are expected to significantly reduce the number of checks required on goods being shipped into the North from Britain.
Minister for Foreign Affairs Simon Coveney said the EU has listened to the North and will announce “far-reaching proposals” to respond to “very real concerns” about the protocol.
He tweeted: “I hope today can be a day to improve relations with NI business and Unionist community in particular. EU making a big effort here.”