Thousands of Greek public sector workers, including teachers, doctors and transport staff, marched in Athens on Thursday during a strike against planned labour law changes by the conservative government, which was re-elected in June.

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

The one-day nationwide strike called by Greece’s largest public sector union ADEDY is the first walkout since the Mitsotakis government’s re-election for a second term.

Trains and buses ran a reduced service, state hospitals operated with emergency staffing and many schools closed.

The protesters marched to parliament, where lawmakers were debating the planned changes, which are expected to be passed this week. Mitotakis’s government has 158 lawmakers in the 300-seat parliament.

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

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 a conflict of interest. It also enables employers to implement a six-day working week.

“It leaves open the door for us to work as many as 13 hours (a day), and until we are 74,” said Lambrini Christoyanni, president of the union representing agriculture ministry employees. “It also puts an end to demands by workers of wage increases – increases that they deserve.”

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 also 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.