The EU’s negotiator wants to de-dramatise the issue of the border
He also said any backstop solution must respect the UK’s territorial integrity.
It comes as Theresa May prepares to win support for her plans from EU leaders.
The UK prime minister will use a dinner in Salzburg on Wednesday to sell her Chequers plan for future co-operation with the EU to the bloc’s 27 other leaders.
Mrs May has insisted there needs to be “friction-free movement of goods”, with no customs or regulatory checks, between Northern Ireland and the Republic, in order to avoid a hard border there.
Six months to go
There is just over six months to go before the UK is due to leave the EU on 29 March 2019.
Negotiations are at a critical stage, with both sides hoping for an agreement on the terms of the UK’s withdrawal and future trade relations by the start of November at the latest.
How is the UK likely to respond?
The UK put forward rival backstop proposals in June, which would see the whole of the UK staying in a customs union with the EU after the end of the proposed Brexit transition period in December 2020.