Around 45,000 people took part Thursday in a national demonstration against the government of Belgian Prime Minister Charles Michel, police said according to the Belga news agency, while transport services were hampered for several hours.
It was the fourth large-scale protest since the centre-right government took office two years ago, introducing initiatives including pension reforms and a controversial overhaul of the 38-hour working week.
The protest was organized by Belgium's three main trade unions to deliver the message that "this is not a happy anniversary." The unions said that 70,000 people had participated in the march through the centre of Brussels, Belga reported.
They marched under slogans such as "Don't touch my 38 hours," and "Dignity comes through a job."
"This government is the most antisocial in the last 30 years," said Rudy De Leeuw, the president of the socialist FGTB trade union, according to Belga. Its secretary general, Marc Goblet, threatened with a general strike if the government does not respond to the syndicates' demands.
Public transport in Brussels ran a skeleton service early Thursday, while regional train and bus services across the country were also affected, Belga reported. National railway services ran normally, allowing protesters to travel to and from Brussels.
Michel's coalition government includes his francophone liberal party, the Flemish liberal party, the Dutch-speaking Christian Democratic party, and - for the first time - the nationalist party N-VA. The government took office in October 2014.