Since 10 pm on Sunday, a nationwide strike in Belgium has disrupted traffic and public services in response to the government's planned pension reform.

The strike especially bears consequences for train, bus, and air traffic, with a dozen connections having been cancelled for Monday. Only around one in three InterCity trains will run on the main routes and most public transport in Brussels will be cancelled.

Belgian residents had already received a warning last week about a strike between 10pm on Sunday and 10pm on Monday. The CFL also advises its customers to check the impact of the strike on CFL.lu or their mobile app.

Air traffic, too, is expected to be severely disrupted. According to the Belgian news agency Belga, around half of Brussels Airlines' European flights are cancelled while Charleroi Airport is expecting “severe disruptions.”

About 40 percent of flights taking off or landing at Brussels airport – Belgium's largest – were cancelled, as baggage handlers, security staff and other personnel downed tools, the company operating the terminal told AFP. Flag carrier Brussels Airlines said on Saturday it was forced to pre-emptively cancel half its flights within Europe to keep long-haul routes running.

The schools in Flanders, the hygiene service, and the post office are also partially affected by the strike. A demonstration of at least 10,000 demonstrators is planned in Brussels. Many teachers, particularly in the Dutch-speaking northern Flanders region, where federal authorities have a say over education, joined the walkout, according to the unions.

The nationwide strike was called by Belgium's three main unions to protest against pension cuts that might be enacted by the incoming government. Belgian parties are still in talks to form a new federal administration following elections in June. Elections were only held six months ago, but the signs are increasingly pointing to a centre-right coalition.

The five parties negotiating to strike a coalition deal plan to raise the retirement age for railway workers and others who are now allowed to retire early, according to CSC, a trade union. Overall "there are at least three billion (euros) in savings planned on pensions", CSC general secretary Marie-Helene Ska told local radio RTBF.