Brexit talks are progressing with "momentum", the British minister in charge of negotiating the divorce said Friday after meeting his EU counterpart, despite warnings from Europe that a deal is still some way off.

After talks in Brussels with EU chief negotiator Michel Barnier, Brexit Minister Stephen Barclay said there was a "shared sense of purpose" to reach agreement and avoid Britain crashing out of the bloc without a divorce deal.

Britain is racing toward its October 31 departure without an exit agreement and faces the threat of economic disruption that the government admits could cause food shortages and spark civil unrest.

Barclay and Barnier discussed three papers submitted by London with ideas on replacing the so-called "Irish backstop" provisions in the Brexit deal struck last year but rejected by British lawmakers.

"There is significant work still to do but there are serious discussions that are taking place," Barclay said after the talks.

"We are moving forward with momentum, talks will continue next week between the technical teams."

But the European Commission, which leads Brexit talks for the remaining 27 member states, gave a more sober assessment, stressing that the British papers amounted to no more than "a first set of concepts, principles and ideas".

And there was further pessimism from Dublin, with Irish Foreign Minister Simon Coveney telling BBC radio that while the "mood music" around talks had improved, a deal was still "not close" and British proposals so far were inadequate.

"What we are being asked to do by Steve Barclay and by others is to replace a guarantee around that border question... with a promise that somehow we'll do our best to try to solve this issue in the future but we don't know how just yet," he said.

"That doesn't sound like a fair deal to me."

Johnson's push

British Prime Minister Boris Johnson insists the backstop, which would temporarily keep Britain in the bloc's customs union to avoid a hard border in Ireland, is undemocratic and unacceptable to London.

But Britain has so far not come up with an alternative that satisfies Brussels or Dublin, and after Friday's talks the commission once again called on London to come up with substantial proposals - suggesting the papers submitted fall short of what is required.

"It is essential that there is a fully workable and legally operational solution included in the withdrawal agreement," the commission said.

"We remain willing and open to examine any such proposals that meet all the objectives of the backstop."

The commission's emphasis on the need for any alternative plan to fully replicate the backstop goes against Barclay's suggestion in a speech in Madrid on Thursday that such a solution was impossible.

He accused the commission of "seeking a purist, identical result" and suggested the deadline for working out a backstop alternative could be pushed back to December 2020.

Brussels has called for a clear alternative well before Johnson attends a potentially decisive EU summit in Brussels on October 17-18.

After a diplomatic push this week which included talks with Commission chief Jean-Claude Juncker in Luxembourg, Johnson will meet with EU Council President Donald Tusk on Monday afternoon on the sidelines of the UN General Assembly in New York.