France on Sunday denied British media reports that President Emmanuel Macron had offered concessions on the Irish backstop to end the stalemate over Brexit negotiations.

The Times newspaper reported over the weekend that France and other EU countries were ready to provide assurances over the Irish backstop, and that Macron had softened his position "to assist a last-ditch attempt by the EU to help to get the withdrawal agreement across the line".

"These [reports] are without any foundation... The French position is that of the European Union: the withdrawal agreement is not renegotiable," an official from Macron's Élysée office said.

UK Prime Minister Theresa May is seeking changes to the most contentious part of her withdrawal agreement: a backstop arrangement to ensure there is no return of a hard border between EU-member Ireland and Northern Ireland after Brexit.

May plans to speak to every EU leader and the European Commission chief to seek changes to her EU withdrawal agreement, days after she suffered defeat in a parliamentary vote that has increased the risk of a "no deal" Brexit.

Macron has championed the EU's refusal to reopen the agreement and water down a provision designed to guard against an Irish hard border.