Belgian Prime Minister Guy Verhofstadt is set to form a new center-left government after his Liberals and their Socialist coalition partners won Sunday's general election. The poll also produced big gains for the anti-immigrant, far-right Flemish Bloc, which has been shunned by the political establishment since it appeared on the Belgian political scene 20 years ago.

The Belgian electorate gave Mr. Verhofstadt's Liberal-Socialist coalition the thumbs-up sign after a four-year term in office.

The Liberal and Socialist parties in Flanders, the Dutch-speaking region where 60 percent of Belgians live, and their counterparts in French-speaking Wallonia increased their vote totals and now hold a comfortable majority in the Belgian parliament.

The Liberals and Socialists are now set to rule without their junior partners, the Greens, who lost heavily in Sunday's balloting. Some commentators said the Greens were punished because of their campaign against tobacco advertising, which cost Belgium its Formula One motor racing Grand Prix.

Mr. Verhofstadt, whose Flemish Liberals got the biggest plurality, said he will proceed with his economic reform program. Pre-election polls showed voters gave his coalition good marks for balancing the federal budget and cutting taxes.

But given the strong showing of the Socialists, who will now hold 48 seats in the 150-member lower house of parliament to the Liberals' 49 seats, Mr. Verhofstadt's political skills face a big test in the weeks and months ahead.

He will have to reconcile the pro-business tendencies of his Liberals with the resurgent Socialists' demands for more spending on social security and healthcare.

He will also have to mend strained relations with the United States over his government's opposition to the U.S.-led war in Iraq and its obstruction of NATO moves to bolster Turkey's defense in the run-up to the conflict.

The most disturbing outcome of the elections to mainstream politicians and middle-of-the-road commentators was the continuing rise of the extreme right Flemish Bloc, which increased its share of the national vote to 18 percent, up from 15 percent in the last elections, in 1999.

The Flemish Bloc, which favors independence for Flanders, campaigned for a tough crackdown on crime and an end to immigration. Mainstream parties immediately reiterated their refusal to have any dealings with the Bloc.

Prime Minister Verhofstadt has handed in the outgoing government's resignation to King Albert II. The monarch will now appoint a go-between to consult the winning parties and set up negotiations for a new coalition. That process could take days, or even weeks, depending on how much haggling goes on.