A DUP MP has accused Dublin's government of acting "disgracefully" over the Irish border and he urged the UK to "shake their cage" in EU talks.
Ian Paisley said the UK should stop "pussy-footing around" if Dublin keeps on frustrating the will of UK citizens.
Mr Paisley said Britain should make fishing policy talks as "long, tedious and hard" for Dublin as possible, unless they started acting differently.
The North Antrim MP made his remarks in parliament, during a meeting of the Northern Ireland Affairs committee.
"They need to start acting in a mature way and deal 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; that they want this part of the sovereign territory of Her Majesty's Government to remain out with the rest of the agreements.
"And I think that needs to be spelt out loud and clear, and if Her Majesty's Government isn't – for diplomat reasons – prepared to say it publicly, I hope that you're starting to shake their cage internally and privately in these negotiations."
He added: "Frankly, a lot of people are really exasperated with the attitude of the Irish government."
Mr Paisley addressed his comments to Northern Ireland Office Minister, Chloe Smith, but she made no direct response.
Earlier, Ms Smith told committee members she could not share details of the government's contingency planning over Irish border issues with them because of "sensitivities" over the Stormont talks, which she said were on-going.
This week, Sinn Féin said they saw no basis for becoming involved in further talks to restore Stormont at the moment.
The Labour MP, Conor McGinn, said there was some confusion of whether talks aimed at restoring devolution were continuing.
He asked Ms Smith if Sinn Féin's statement contradicted the government's position.