Greek public sector workers including teachers, doctors and transport staff walked off the job on Thursday to protest against labour law changes the conservative government plans, months after it was re-elected.

Prime Minister Kyriakos Mitsotakis’ government says the overhaul would eliminate undeclared work and boost employment overall, but the opposition says it is an assault on workers’ rights and would create “barbaric” conditions.

Trains and buses were operating on reduced hours during the one-day nationwide strike called by Greece’s largest public sector union ADEDY. State hospitals operated on emergency staff and many schools closed.

Workers were expected to rally in central Athens and later march to parliament to coincide with a debate and vote.

“We demand the bill’s withdrawal,” said ADEDY, which represents about half a million workers.

The walkout is the first against Mitsotakis’ government since he was re-elected in June.

The bill would allow full-time employees to get a part-time second job and work up to 13 hours a day unless certain terms apply such as conflict of interest. It also enables employers to implement a six-day working week if needed.

According to the bill, an employee can be fired within the first year of work without warning or remuneration, unless agreed otherwise.

It allows a probation period of up to six months, but also obliges employers to provide detailed terms of work.

Employers face a fine up to 10,500 euros ($11,175) if they fail to declare an employee’s extension of working hours or change of shifts.

The bill introduces fines and a six-month jail term against those who obstruct employees from working during a strike.

Lawmakers with the main opposition, the Syriza leftist party which is expected to elect a new leader on Sunday, said earlier this week that the government was pushing “a secret agenda” against workers.

Greece’s Communist Party KKE has called the bill “monstrous”.