Boris Johnson's UK government "doesn't give a damn about Ireland", Sinn Féin's Pearse Doherty says.
He was speaking after it emerged that proposed UK immigration laws would see non-Irish EU and EEA citizens have to apply for online pre-clearance to enter Northern Ireland.
The measure is contained in the controversial Nationality and Borders Bill, which is currently making its way through the UK parliament.
British government ministers have said the system would be similar to the ESTA system in place for those travelling to the US.
They've also stressed the UK will not be checking paperwork at the border.
Despite those assurances, there has been very strong criticism of the proposal from a number of parties in Ireland and Northern Ireland.
Stephen Farry of the Alliance party said the proposed "US-style visa waivers" would create new bureaucracy and legal uncertainty for the EU citizens who regularly cross the Irish border.
Speaking in the Dáil this afternoon, Sinn Féin's Pearse Doherty says it's "actually bizarre" that such a measure is even being discussed.
He said: “It’s so disgraceful and such a shameful measure. It threatens the tourism sector in my own region of the north-west, it places massive stress on residents here from other EU countries, and undermines the Good Friday Agreement and the Common Travel Area.
“Ireland once again faces the prospect of the collateral damage of a Tory government in Westminster that doesn’t give a damn about Ireland.
"It’s so divorced from the reality of life on the border that it could actually countenance a measure such as this.”
He asked Tánaiste Leo Varadkar what the Government will do to make absolutely it clear that this is “not on”.
Mr Varadkar said the proposal doesn't come as a major surprise.
He said: "If you recall, part of the argument in favour of Brexit was about controlling their borders and also reducing and stopping immigration from the European Union.
"It may be the case that some people who voted for Brexit didn't realise that... but it is part of the outworking of Brexit.
He added that ministers here will "absolutely" communicate their "concerns and objections" about the proposals to their counterparts in the UK.
It comes amid the ongoing dispute between the UK and EU over the operation of the Northern Ireland Protocol - with US President Joe Biden among those warning the UK against a 'closed border' on the island of Ireland.