Prime Minister Stefan Löfven voiced his concerns in a speech given to trade union confederation LO’s annual congress on Monday morning.
“We can’t be gripped with panic, but we are waking up to a new political reality,” he said.
A Leave vote in the June 23rd referendum could endanger the European Union’s future, the Prime Minister told news agency TT after the speech.
“We don’t know exactly what the effects will be or what forces they might trigger in Europe,” said Löfven.
He added that there was concern in the EU that a Leave vote in Britain would give fresh impetus to Eurosceptics in other countries to push to leave the union or to renegotiate their membership terms.
“It’s not a good time now to have divisions in the EU,” said Löfven.
The government was working on a plan for how to proceed if Britain left the EU, he said, with Sweden seeking to preserve its good trade relations with both the UK and the rest of the EU.
“But there’s not going to be an collapse, panic, or chaos in Sweden [if Britain leaves]. We’ll manage it,” he said.
Foreign Minister Margot Wallström was in Luxembourg on Monday for a meeting with her EU counterparts. Although the British referendum is not officially on the agenda, it was the main topic of conversation in the corridors, she said.
“On the fringes we’re talking about it all the time,” said Wallström.
With the result set to be announced on Friday, Midsummer Eve, she admitted: “It’s very exciting and I am a bit nervous.”
Wallström expected EU leaders to have plenty of work to do even if Britons vote to stay in the 28-member club, with negotiations set to begin within days on new memberships terms.
“It won’t be easy if they remain either – there’s a series of exceptions on which there are likely to be tricky discussions.”