BRUSSELS — A national strike to demand higher pay has paralyzed airports, sea ports and rail traffic in Belgium, while hundreds of factories are shut down for the day.

Trade unions are protesting limits on wage increases during times of economic growth and want better conditions for early retirement, minimum wages and better education on the job.

The centre-right government of Charles Michel is not in a position to forcefully react to such demands at the moment since it is in a caretaker capacity after the coalition broke down late last year.

There were almost no flights landing at or departing from Belgian airports on Wednesday since air traffic controllers could not guarantee safety with a skeleton staff.