BRUSSELS: Trade unions on Wednesday mobilised about 100,000 workers for the second time in a year to protest the free-market regulations and austerity measures that the center-right government has been pushing through during its first year in office.

And just like in November, the end of the demonstration was marred by violence when a few hundred people confronted police and pelted them with rocks and bottles before authorities drove them back with tear gas and water cannons.

Police said more than 80,000 people joined Wednesday's protest while trade union claimed 100,000 took part, just 20,000 short of last year's demonstrations.

Belgium's three main unions joined Wednesday behind a common platform, arguing that the government of Prime Minister Charles Michel is promoting big companies at the expense of the workforce.

The unions specifically complain about a freezing of the link between inflation and wages, an increase of the retirement age, cuts in social services and tax measures that they claim unfairly benefit employers.