Demonstrators described the amendment as "modern-day slavery".

Thousands of protesters marched in Greece on Thursday as part of a nationwide 24-hour strike against a new labor law that demonstrators referred to as a form of "slavery".

More than 16,000 people participated in separate demonstrations in Athens organized by unions and political parties, while leaders of the left, socialist and communist parties attended the rallies.

The 24-hour strike led to the suspension of ferry and train services, the rescheduling of flights, and the suspension of most public transport in Athens.

In this regard, Greek Communist Party leader Dimitris Koutsoumpas said: "No matter what the government does, workers condemn this bill...it should be in the trash."

Protestors referred to the amendment as "modern-day slavery" because work hours are to be extended.

The government notes that the amendment, which Parliament will vote on next week, allows for voluntary flexibility in work hours, sets rules regarding remote work, and improves the maternity and paternity leave, in addition to provisions that protect against sexual harassment in the workplace.

Labor Secretary Kostis Hatzidakis said the new rules will allow employees to negotiate the option to work longer hours during part of the year and take an additional leave later.

The amendment allows for an increase in working hours to ten in exchange for an additional paid leave.

Partisan Objection to the Legal Amendment

For their part, unions and political parties considered that the amendment undermines collective bargaining, disrupts the personal lives of employees, and formalizes the exploitation of overtime by employers (especially large companies), which has been happening for years.

Prime Minister Kyriakos Mitsotakis' conservative government said the measures would modernize "antiquated" laws dating back decades to a pre-internet time when most workers clocked into their offices and factories at the same set hours.

The unions also oppose the amendment's imposition of stricter rules for dealing with calls for strikes.

The government's majority in Parliament approved the bill during the first reading on Wednesday, ahead of a voting session for the entire parliament next week.

A banner was placed near the Labour Ministry in central Athens read "Hands off the 8-hour workday."

The left-wing Syriza party said the bill was a "monstrosity" and called on the government to withdraw it.

"They will not take us back to the 19th century," Syriza stressed.