STOCKHOLM -- Sweden's Social Democratic minority government will face a vote of no confidence in Parliament either on Wednesday or Thursday this week, the speaker of the House said.

The opposition moderates party submitted a motion of no confidence on Monday when the new Parliament elected on September 15 convened for its first session.

Under Sweden's Constitution Prime Minister Goran Persson's cabinet does not need to win the no-confidence vote to stay in office. It is enough if he can avoid an absolute majority -- at least 175 votes in the 349-seat assembly -- against him.

The social democrats and their ex-communist left party allies have 174 seats.

A four-party center-right bloc has 158 MPs and the environmentalist greens 17. If all of them vote in favor of the moderates' no-confidence proposal, Persson, prime minister since 1996, must resign.

Political and financial market analysts regard a social democratic government as the best choice from the point of view of securing a "yes" majority in a referendum on euro membership expected next year.

The prospects of Sweden joining Europe's single currency have boosted the crown and reduced the risk premiums on Swedish government bonds over euro zone state debt during the past year.