Speaking exclusively to Sky News during a three-day visit to the UK, President Borut Pahor added that Britain needs to show “clarity and consensus” and come back to the EU with a plan MPs can approve.
His comments came as the bloc’s chief negotiator Michel Barnier said he is ready to give Britain more guarantees that the Irish backstop is only intended to be temporary.
The backstop is a customs plan to avoid a “hard” border between Ireland and Northern Ireland if a free trade deal between the UK and EU is not reached.
It has become the main point of contention in the proposed Brexit deal.
President Pahor said he wanted a compromise on the Irish backstop to be found, but added that Slovenia would not approve a deal that Ireland disagreed with.
He told Sky News: “It is not clear at the moment if United Kingdom has a clear position on some sort of compromise solution and if it fits the requirements of the majority in the House (of Commons).”
On the possibility of a delay to Brexit, he added: “I think Slovenia and a lot of other countries would say yes.
“I think that nobody wants to see a hard Brexit in a chaotic way.”
However, the former EU politician said a delay to Brexit would not make a compromise any easier to find and expressed concern the European Parliament elections at the end of May could cause problems.
He said: “If Brexit would become an issue of political campaign among the 27 (member states), I think this could even make more difficult the whole framework of negotiations between London and Brussels.”
It comes after Prime Minister Theresa May promised MPs the possibility of a vote to delay Brexit if the Commons rejects her deal for a second time.
Speaking on the issue of the Irish backstop, Mr Barnier told Germany’s Die Welt newspaper: “We know that there are misgivings in Britain that the backstop could keep Britain forever connected to the EU.
“This is not the case. And we are ready to give further guarantees, assurances and clarifications that the backstop should only be temporary.”
It has become the main point of contention in the proposed Brexit deal.
Mr Barnier added: “We will not reverse the backstop.
“It’s an insurance.
“We don’t want to make use of it. And this is also the case when you insure your house. It’s only intended for the worst-case scenario.”
Foreign Secretary Jeremy Hunt said last month that the key to securing a Brexit deal that the British government can get through parliament was to define the “temporary” nature of the backstop more precisely.
Mr Barnier added EU guarantees that the backstop is temporary could come as part of the political agreement setting out expectations for Britain’s relationship with the bloc after it leaves.
He said that he saw little risk of the remaining 27 EU leaders opposing a delay to Britain’s exit, currently set down as 29 March, as long as Britain was serious about finding a solution.
He added that any decision to allow an extension would have to be unanimously approved by EU leaders at a summit on 21 March.
President Pahor has spoken days after Mr Hunt visited Slovenia and incorrectly claimed the country was a “Soviet vassal state”.
The former speaker of Slovenia’s national assembly Milan Brglez criticised Mr Hunt for “arrogantly lecturing” his country.
President Pahor said the foreign secretary had “started explaining his position”, adding that he had “taken this as an apology and the story is over”.
He added: “We should not make mistakes about our past because every country is proud of its history.”
Slovenia was in fact the wealthiest state within the former Yugoslavia and was outside of the Iron Curtain.