Sweden's parliament speaker has tasked opposition leader Magdalena Andersson with forming a new government, following last week's general election in which the left-wing bloc secured a slim majority.

Andersson, leader of the centre-left Social Democrats and a former prime minister, was formally asked by Parliament Speaker Andreas Norlen on Friday to begin coalition talks.

Norlen's request follows the resignation of centre-right Prime Minister Ulf Kristersson, who stepped down on Thursday after the election result was confirmed.

The left-wing bloc won 176 of parliament's 349 seats, securing a majority of three seats. The centre-right bloc, led by Kristersson, won 173 seats.

"I have now been tasked with exploring the possibility of forming a government. A task I undertake with great humility and will act constructively to put together a new government," Andersson said in a statement.

"My approach to the work that is now taking place is that all political forces now need to put party tactics aside and put Sweden and the Swedish people first."

Andersson is expected to seek the support of three other left-wing parties: the Greens, the Centre Party, and the Left Party. However, significant differences between the parties are likely to complicate negotiations.

The socialist Left Party has said Andersson will need to award some of its members cabinet posts in order to secure their backing. The liberal Centre Party, meanwhile, has ruled out supporting a government that includes the Left Party in cabinet.

Andersson has until September 28 to form a government. If she fails, Kristersson will be given the opportunity to attempt to form a coalition.

Coalition and minority governments are common in Sweden, as the country's political landscape is divided into two major blocs, each containing four parties. The process of forming a government following the 2022 election took more than a month.