Ireland's deputy prime minister, Micheal Martin, warned Monday that progress towards a deal between London and Brussels on Northern Ireland's post-Brexit trade rules should not be endangered by political manoeuvres.

British news reports over the weekend, citing unnamed sources, said former British prime minister Boris Johnson had come out strongly against ceding ground to Brussels by abandoning a bill he introduced that would unilaterally rewrite the trade protocol.

This was widely seen as a political challenge to Johnson's successor, Prime Minister Rishi Sunak, who met European Commission President Ursula von der Leyen in Munich over the weekend amid optimism that a deal to resolve the standoff was close.

But a Downing Street source refused on Monday to be drawn on timing for any deal, saying only that the talks were "continuing".

Arriving at a meeting of EU ministers in Brussels, Martin said "very good progress has been made" in the talks but he did not believe that the face-to-face between Sunak and von der Leyen "was meant to be the culmination of this entire process".

Martin did not directly address Johnson's reported intervention in the British debate.

But he warned: "I think what's really important is that everybody now, from here on, thinks about the people of Northern Ireland -- not powerplay, not politics elsewhere.

"I think the people of Northern Ireland have had enough of that, of people playing politics with their future," he said.

He hailed the "sincere and substantial" attempt by the UK and EU negotiators to resolve "legitimate concerns" that some in Northern Ireland had about the deal.

- Domestic pushback -

Despite giving a positive tone after his meeting with von der Leyen, Sunak faces strong pushback domestically against a revision of the trade deal.

Opponents are especially vigilant against changes that would see EU single market laws continue to apply in Northern Ireland, even if lighter-touch rules favoured by both sides were introduced.

Northern Ireland's Democratic Unionist Party (DUP), which is refusing to re-enter a power-sharing government in Belfast, opposes implementation of the protocol, which has the province remaining in the EU single market after the rest of the UK left.

Sammy Wilson, a senior DUP lawmaker in Westminster, accused the British government of going into the talks with "an attitude of defeat" and played down prospects for a deal this week.

Johnson approved and signed the protocol as part of the Brexit withdrawal agreement.

But his government then refused to implement it amid claims from unionists that the imposition of some border controls between Northern Ireland and Great Britain would weaken UK unity.

"We are British and we expect to be governed by British law, not Brussels law. We would certainly not collaborate in administering Brussels law in our part of the United Kingdom," Wilson told Sky News.

Ardent Brexiters in Sunak's party are backing the DUP's hard line, reportedly with support from Johnson.

There was no immediate comment from 10 Downing Street.