He was expected to name Social Democrat leader Löfven after his party on Friday reached a deal with two former opposition rivals and the Green Party.

But this deal would have also required the Left Party – who were not only not a part of the deal, but who were explicitly excluded from influence during the coming term by the deal – to either vote in favour or abstain, in order for Löfven to pass a parliamentary vote.

Left Party leader Jonas Sjöstedt told reporters on Monday afternoon that his party was not prepared to do this, “if the situation remains unchanged”.

“We see problems. We are both surprised and disappointed by how far Stefan Löfven has been prepared to go to the right,” said Sjöstedt, who also described the proposed government agreement as “trying to push us out of normal political influence”.

He stressed that the Left Party wanted to see Löfven stay on as prime minister, but said that the two parties would need to carry out further talks. 

Sjöstedt would not specify exactly what changes he was hoping for, but said: “There are some unreasonable aspects that need to be dealt with first. We are looking for routes forward. We are going to use the coming days to find solutions, which I'm convinced Löfven also wants.”

Under the proposed agreement, the Social Democrats and Green Party would govern with backing from the Centre and Liberal parties. The latter two parties have been part of the centre-right Alliance in opposition to the Social Democrat-Green coalition for the past four years.

TIMELINE: Everything that's happened in Swedish politics since the elections

Photo: Magnus Hjalmarson Neideman/TT

Any potential Swedish government does not need a majority of MPs to vote in its favour in order to govern; the system of negative parliamentarianism instead just requires that a majority does not vote against it. This system, which favours the formation of minority governments, means that parties can give 'passive support' such as abstaining in the prime ministerial vote, allowing the government to pass.

However, the four parties included in the agreement have only 167 seats between them, which means they do not have a majority among parliament's 349 members.

Assuming that the right-wing parties – the Moderates, Christian Democrats and Sweden Democrats – will vote against the deal, this means that Löfven needs the Left Party's 28 MPs to either vote in favour or abstain in Wednesday's prime minister vote in order to avoid a majority of 'no' votes.

Sjöstedt said that he had suggested that parliamentary speaker Norlén postpone the vote planned for Wednesday. Green Party spokesperson Isabella Lövin said her party also hoped the speaker would give the parties extra time before a vote.

Earlier on Monday, Löfven stressed that he had appreciated working together with the Left Party, who were involved in budget negotiations during the last term, but that it had been important to the centre-liberal parties to stake out a new political course.

He said that it would be possible to cooperate with the Left Party on political issues not included in the four-party agreement, but that the agreement itself could not be changed.

The number of votes on prime ministerial candidates that can be held before a second election is forced is capped at four. If a vote does take place on Wednesday, it would be the third such vote, after both Löfven and Moderate Party leader Ulf Kristersson have earlier been rejected by parliament.

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