The European Union’s chief Brexit negotiator has told the European Parliament that the remaining 27 EU member states will not be expected to pay for Britain's exit from the bloc.

Updating MEPs on the EU's negotiations with the United Kingdom, Michel Barnier said the taxpayers of the 27 will not have to pay for a decision they did not take.

"No more, no less," he said, to a round of applause from parliamentarians.

On Northern Ireland, he said solutions will have to respect the integrity surrounding the legal order of the EU and the Good Friday Agreement.

He noted that the Common Travel Area will require detailed work, which he said both the EU and the UK are committed to.

Guy Verhofstadt, who is the European Parliament's Brexit negotiator, told MEPs that he visited Northern Ireland for the first time recently and it struck him that the problems are not over, and despite peace, tensions remain.

"There are fences 12 metres high and this is in the 21st Century," he said.

The leader of the Alliance of Liberals and Democrats stressed the importance of the Good Friday Agreement for Northern Ireland, saying that if a border returns, violence will return.