UPDATE 1-Swedish Social Dems leader Lofven asked to try to form new govt

The speaker of Sweden's parliament said on Monday he had asked Social Democrat leader and caretaker prime minister Stefan Lofven to try to form a government after the head of the centre-right opposition gave up a similar attempt at the weekend.

A general election on Sept. 9 delivered a hung parliament with the anti-immigration Sweden Democrats holding the balance of power, although neither the centre-left nor centre-right bloc is willing to do a deal with them.

Moderate Party and centre-right Alliance bloc leader Ulf Kristersson had a first stab at forming a government but failed.

Lofven's chances look little better.

"The parties have to rethink where they stand if we are going to get further in this process," Speaker Andreas Norlen said.

Lofven, who has two weeks to find a workable government, lost a vote of no-confidence as prime minister on Sept. 25.

His centre-left bloc of the Social Democrats, Greens and Left party has 144 seats in the 349-member parliament, one more than the centre-right Alliance.

The Sweden Democrats, with roots in the white supremacist fringe, have 62 seats.

Lofven is hoping to get support from the Centre and Liberal parties - currently part of the Alliance bloc.

Those two parties scuppered Kristersson's attempt at forming a government over the weekend, saying his proposals would leave the government needing support from the Sweden Democrats.

The leaders of the Centre and Liberal parties, however, said they still wanted to see Kristersson as prime minister, backed by broad bipartisan support.

(With inputs from agencies.)