The UK should not seek convergence with EU regulations after Brexit, a senior Democratic Unionist said.
Ian Paisley urged better post-separation co-operation between Northern Ireland and the Republic of Ireland as negotiations continue to break the deadlock over the Irish border.
But he said matching the two countries' red tape in areas like agriculture was not the way ahead.
He told RTE that issues of post-Brexit convergence with EU regulations needed to be negotiated one by one.
"I am up for co-operation, I believe co-operation between our two states is good and in many areas is vital."
Mr Paisley is one of 10 DUP pro-Brexit MPs who are propping up the British Government on key votes.
He again voiced his party's strong opposition to any outside interference with Northern Ireland's exit from the EU and urged the Republic to take a more "mature" approach.
"If the Republic of Ireland is going to keep shouting at our border and telling us that it is all doom and gloom and we are not going to get a proper relationship, that interferes in the negotiation process.
"All of us, every constituent part, Northern Ireland, Scotland, Wales and England, are leaving the EU.
"Don't undermine our position and our sovereign integrity."
Adhering to certain EU policies would hold Northern Ireland back, the North Antrim MP added. That included areas like agriculture.
"We are not about convergence here, we are about co-operation."
Previously Mr Paisley suggested the UK should make life hard for the Republic of Ireland over a post-Brexit fisheries deal as a response to its "disgraceful" behaviour in the negotiations.
Taoiseach Leo Varadkar has said he does not think Ireland will need to use its veto at the crucial Brexit summit in Brussels next month.
The Irish Government has an option of playing an ace card to block progress in crunch negotiations on the UK's exit from the European Union if it determines there is insufficient certainty on the future of the Irish border.
The British Government is reportedly close to reaching a solution on the Irish border after Brexit.
The issue is a major sticking point in the negotiations and must be dealt with before trade talks can begin.
Efforts to reach a deal are to intensify with Taoiseach Leo Varadkar to hold talks with European Council President Donald Tusk in Dublin tomorrow.
John Walsh, Deputy Ireland Editor with The UK's Times newspaper, outlines how agreement on the border may be achieved:
He said: "The one thing that the EU doesn't want is a divergence in regulatory standards between the north and south of Ireland, if that was to happen then you would need a hard border.
"But if Belfast had powers to set its own regulatory standards then there would be a basis of an agreement where you could get regulatory convergence between the north and south that would obviate the need for a hard border."