DUP MP Ian Paisley has described the Dublin government's behaviour during ongoing Brexit negotiations as 'disgraceful'.
Speaking in a House of Commons committee, the North Antrim representative suggested the UK should make life difficult for the Republic over a post-Brexit fisheries deal in response to them "trying to frustrate the will of the people of the United Kingdom".
Mr Paisley said fisheries waters used by Irish boats would become UK waters after Brexit, adding, "As early as September in 2019 they will need to make a fisheries deal, not with the rest of the EU, but with us, and, frankly, if they continue to exacerbate our will as citizens of the United Kingdom, I think we should make that fisheries deal extremely long, tenuous and hard for them," he said.
"I think that message needs to be spelt out, that they need to start acting in a mature way and dealing with us as good neighbours and as friends instead of trying to frustrate the will of the people of the United Kingdom, by saying they want a united Ireland, they want this part of the sovereign territory of her Majesty's kingdom to remain out with the rest of the agreements.
He said if the UK government was not prepared to say that publicly to the Dublin administration, he said it should start to "shake their cage internally and privately".
The Northern Ireland Affairs Committee was hearing evidence from Brexit Minister Robin Walker and Northern Ireland Office minister Chloe Smith.
Referencing the stance the UK should take with the Dublin government, Mr Paisley told the witnesses the "pussyfooting needs to stop".
"I think our neighbour has acted disgracefully," he said.
Mr Paisley was referring to Ireland's position that, in order to avoid a hard border post-Brexit, Northern Ireland should continue to comply with European regulatory frameworks - even if the rest of the UK leaves the customs union and single market.
He said the UK had loaned Ireland "billions" of pounds to bail it out of "economic ruin and bankruptcy".
Mr Paisley also told the committee that the collapse of powersharing at Stormont could have a positive impact on Brexit, in the absence of MLAs there to object to EU withdrawal plans.
He said, "There might actually be a fortuitous moment arising that it's actually this parliament who will scrutinise Brexit through its members of parliament who actually come here.
"Frankly if this goes back to the parliament (Stormont) in its current make up, all we will get is carping, blocking and attempts to undermine Brexit as opposed to a proper scrutiny of the Brexit negotiations. Is that not the case, that at this point the Assembly could actually damage Brexit?"
Ms Smith told the committee that discussions remain ongoing with the political parties in Northern Ireland in an attempt to reach an agreement to return to powersharing.
She said, "We are continuing work at every level to be able to get that to a successful conclusion. Meetings have taken place."
Asked whether that was a contradiction of comments made by Sinn Féin's Stormont leader Michelle O'Neill earlier this week when she said there was no basis for talks to continue, Ms Smith replied, "Meetings are continuing."
She added, "Whether I agree with Michelle O'Neill or not that there is no basis, there is a clear basis for an agreement to be found, the number of issues which remain to be resolved is limited in number and possible to overcome."
However, Ms Smith did not elaborate on the nature of discussions or if they amounted to official negotiations.
A summit meeting will be held on December 14 in Brussels with the heads of government of the EU states.
Progress on Brexit negotiations will be considered at this stage, with the border on the island of Ireland expected to be among the core issues focused on.
SDLP MLA Claire Hanna responded to Mr Paisley, saying. "The Irish Government has a responsibility to protect the interests of people on this island and to protect the Good Friday Agreement. They are living up to those obligations.
“Any suggestion that UK fisheries policy should be formulated on the basis of punishing Irish people and Irish businesses is absolute madness. But more than that, it will hurt businesses in the North who rely on cooperation across this island, particularly in the agri-food sector," she added.