The Taoiseach has told the Dáil that the Northern Ireland Protocol Bill passing the second stage in the UK parliament is the latest "regrettable and unacceptable" instance in "a trend towards unilateralism".

Micheál Martin said that he has spoken to the President and Vice President of the European Commission, and the President of the European Council, and he said Ireland will "work absolutely in concert" with EU allies on a shared approach.

Mr Martin made the comments in response to a question from Sinn Féin leader Mary Lou MacDonald in the Dáil.

Mary Lou McDonald in the Dáil

Mr Martin's comments come after the UK government's bid to scrap parts of the Northern Ireland Protocol cleared its first hurdle last night, despite EU warnings it is illegal and could spark a trade war.

MPs in the House of Commons voted through the controversial Northern Ireland Protocol Bill by 295 votes to 221 after a debate, allowing it to progress to the next stage of scrutiny in parliament.

British Prime Minister Boris Johnson, in Germany for a G7 leaders meeting, earlier insisted the legislation was needed to remove "unnecessary barriers to trade from Great Britain to Northern Ireland".

"All we're saying is that you can get rid of those, whilst not in any way endangering the EU single market," he told reporters.

Mr Martin has previously said that "any unilateral decision to breach international law is a major, serious development".

"There can be no getting out of that," he said, also warning against another government bill to revamp human rights in the UK that could affect the Good Friday Agreement.

In the House of Commons, Mr Johnson's predecessor as prime minister Theresa May, who quit after failing to get parliamentary backing for her own Brexit divorce deal, said she could not back the bill.

It was "not legal... will not achieve its aims and... will diminish the standing of the United Kingdom in the eyes of the world", she told MPs.

The UK government unveiled its plan to unilaterally change trading terms for Northern Ireland earlier this month, prompting the EU to pledge legal action.

Brussels says overriding the deal it struck in 2019 with Mr Johnson's government breaches international law, and has warned of trade reprisals, which Britain can ill-afford as prices surge on the back of the war in Ukraine.

Days of further scrutiny and subsequent votes now loom, and despite winning the vote, Mr Johnson is facing criticism among some of his own Conservatives after he only narrowly survived a no-confidence vote this month.