British Ministers have been urged to take a "no surrender attitude to the EU bureaucrats" by a DUP MP.
Ian Paisley accused the bloc of trying to blackmail and bully Britain as he asked an impassioned question in the Commons.
His comments came as MPs pressed Northern ministers for further details about Brexit and how the Irish border issue will be addressed.
Northern Ireland Secretary Karen Bradley and minister Shailesh Vara reiterated the UK's commitment to maintain a frictionless border, without undermining the integrity of the UK.
North Antrim MP Mr Paisley said: "Does the minister agree with me that it's about time the Government demonstrated a no surrender attitude to the EU bureaucrats, who try to blackmail us, bully us, over air flights, passenger duty and everything else.
"Stand up to them man, and stand up to the EU and let's get on with leaving the EU."
Mr Vara replied: "The Prime Minister will stand up to anyone and everyone when it comes to maintaining the best interests of the United Kingdom."
There was further criticism of the EU and Irish ministers by DUP MPs during Northern Ireland questions.
Jim Shannon (Strangford) urged trading with Ireland to continue "unhindered by petty point scoring, statement making, headline grabbing whims of EU leadership".
Sammy Wilson (East Antrim) raised concerns about "the frictions in relationships between the UK Government and the Irish Republic".
He added: "What comment has he got to make about the threat issued by the foreign minister yesterday, that he will block negotiations if he does not get the legislation produced to force the Northern Ireland assembly to introduce EU regulations."
Mr Vara said the Brexit tales would be difficult but all parties were committed to being flexible and coming up with solutions.
Elsewhere, shadow Northern Ireland minister Stephen Pound asked whether an electronic border was "feasible or is it just a fantasy".
Ms Bradley said: "We are determined there will be no new physical infrastructure at the border and we will maintain things like the Common Travel Area, which has been in existence since well before the EU."
SNP spokeswoman Deidre Brock questioned if Britain leaving the customs union would mean a divergence of regulations on the island of Ireland.
"Will she tell us what, and I quote, specific solutions to address the unique circumstances of the island of Ireland she is proposing," she added.
Ms Bradley said: "There are unique circumstances in Northern Ireland, unique to anywhere across the whole of Europe, and those unique circumstances have to be reflected.
"The UK Government's intention is that we resolve the matter of north-south trade and east-west through the overall UK EU agreement.
"But we are absolutely determined to make sure that we respect the integrity of the north-south border and that we respect the agreements that were made in Belfast nearly 20 years ago."
Mr Vara added: "Let's be absolutely clear. We have said that we will be leaving the customs union and we will be leaving the single market as well.
"What we hope to do is, in phase two, engage in those negotiations to make sure that we have the best possible trade deal that we possibly can have with the European Union, but we are committed to having a frictionless border."