Thursday is general strike day in Spain and night shift workers were the first to down tools.
Unions have called a 24-hour walkout the day before Prime Minister Mariano Rajoy announces a new round of deep budget cuts.
The stoppage is against changes to workers’ rights already passed by the government.
In Madrid thousands gathered hours before the start of the strike claiming the labour legislation was ‘useless inefficient and unfair’.
Companies can now lay workers off, cut wages or change conditions if citing productivity reasons.
The budget expected on Friday is set to feature tens of billions of euros in deficit-reduction measures. Their aim is to help Spain in its struggle to satisfy both the European Union and international investors and to avoid the need for a bailout.
Early polls showed that only 30 per cent of workers would take industrial action but an electoral setback last Sunday for the ruling People’s Party could encourage more to participate.