The United Kingdom is due to leave in 30 days but Prime Minister Theresa May has so far failed to get parliament to ratify the deal she agreed in November and on Tuesday opened up the possibility of a delay until the end of June.

European leaders want to avoid a disorderly no-deal Brexit that would send shockwaves through the economy of the EU 27, though they are also exasperated at Britain's labyrinthine divorce crisis and want to move on.

"If the British need more time, we would support an extension request if it was justified by new choices from the British," Macron said in joint press conference with Germany's Chancellor Angela Merkel in Paris.

"But we would in no way accept an extension without a clear view on the objective pursued," he added. "As our negotiator Michel Barnier said, we don't need more time, we need decisions."

Mrs Merkel said she was "totally on the same line" as Macron but appeared more willing to show flexibility.

"If Britain needs some more time, we won't refuse but we are striving for an orderly solution ie an orderly exit of Britain from the European Union," she said.

"We regret this step but it is reality and we must now find a good solution."

May made major shifts on Tuesday under pressure from UK lawmakers who accused her of running out the clock.

She will hold a vote within two weeks on her deal, and said that if it fails she will offer politicians chances to vote on whether to leave with no deal, or to ask the EU for a delay.

Those concessions took much of the heat out of a series of votes in parliament planned for Wednesday, in which opposition lawmakers and rebels in May's own Conservative Party had planned to demand more control to rule out leaving with no deal.

Australian Associated Press