European Union President Donald Tusk said on Tuesday that the bloc's "hearts are still open" to Britain if it changes its mind about leaving, in a fresh suggestion that Brexit could be reversed.

Tusk's comments, which European Commission chief Jean-Claude Juncker said he hoped London would heed, come shortly after talk about whether Britain should hold a second referendum on EU membership.

"If the UK government sticks to its decision to leave, Brexit will become a reality with all its negative consequences in March next year, unless there is a change of heart among our British friends," Tusk told the European Parliament to light applause.

"Wasn't it (British Brexit minister) David Davis himself who said if a democracy cannot change its mind it ceases to be a democracy?" he told the assembly in Strasbourg, France.

"We on the continent haven't had a change of heart. Our hearts are still open to you."

The former Polish premier stressed however that the remaining 27 EU states would push ahead with negotiations with Britain on its departure, urging London to say what it wanted in terms of post-Brexit ties.

"As regards our future relations, what we need today is more clarity on the UK's vision. Once we have that, the leaders will meet and decide on the way that we see the future relationship with the UK as a third country," Tusk said.

Juncker meanwhile echoed Tusk's comments, which are far from Tusk's first suggestion that bloc would be open to Britain changing its mind and rejoining the European fold.

"Tusk said our door still remains open and I hope that that will be heard clearly in London," he said.

The issue of a second referendum after Britain's original vote to leave in June 2016 returned to the agenda last week when leading Brexit campaigner Nigel Farage suggested he was open to the idea.

Farage later walked back the comments.

Source: AFP