Paris - British Prime Minister Boris Johnson and French President Emmanuel Macron have set out starkly different positions on a possible Brexit deal, as Britain faces the prospect of leaving the bloc on October 31 with or without an agreement.

Further negotiations

Even though the two leaders agreed that further negotiations could take place over the next 30 days, Macron insisted on provisions to keep an open border in Ireland while Johnson declared that they were not necessary.

Ahead of a working lunch in the Elysee Palace, Johnson said he had been "powerfully encouraged" by German Chancellor Angela Merkel's suggestion that a solution could be sought in the next 30 days.

The so-called backstop for the border between Northern Ireland - part of the United Kingdom - and EU member state the Republic of Ireland could be replaced by technical measures such as trusted trader schemes and electronic pre-clearance, Johnson said.

Those ideas have previously been proposed by hardline pro-Brexit lawmakers in London, but the Irish government dismissed them at the time.

Integrity of single market

Macron warned that the backstop, negotiated as part of Britain's withdrawal agreement by Johnson's predecessor Theresa May, was not just a technical measure but indispensable "to preserve stability in Ireland, for the integrity of the single market."

A "solution" about the deal should be possible within 30 days "if there is good will on both sides," Macron said, but it would not be possible in that time to come up with a new deal that was greatly different from the existing one.

British negotiators and the EU team led by Michel Barnier would work to "try and find what could amount to elements of constraint without changing the fundamental balances of the withdrawal agreement," Macron says.

Johnson made it clear that he was prepared to leave the EU without a deal, arguing that even in that case checks on the Irish border would not be necessary.

"Under no circumstances will the UK be putting checks at the frontier and we don't think it's necessary from the point of view of the EU to do that to protect the integrity of single market," he said. "We think there are other ways of doing that."

The backstop negotiated by May would keep Britain in the EU customs area and align Northern Ireland with some key EU market regulations unless and until long-term alternative arrangements were made.

Smooth and pain free exit

The EU and the Irish government have insisted that it is needed to shore up a 1998 peace agreement that ended almost 30 years of civil strife in Northern Ireland, where many in the Catholic minority still favour unification with Republic.

Leaving without a deal could cause problems for traders and migrants from both sides.

But Johnson said that he wanted to "do all the necessary work, on both sides of the [English] Channel, to make sure that whether we get an agreement or not our exit is as smooth and as pain free as possible for citizens and business on both sides."

Luxembourg's Foreign Minister Jean Asselborn has also sounded a note of caution about the prospect of replacing the backstop in the coming weeks.

"Miracles can never be ruled out, but I am sceptical that something can be plucked out of the air that guarantees Ireland will not have a hard border and that the EU will have control over what comes into the market," Asselborn told German public broadcaster SWR.