Athens transport authorities have launched legal action against unions representing metro workers after they called a fifth consecutive day of strike action on Monday and heralded further action for Tuesday.

Initially, metro employees intended to hold a work stoppage but later decided to make this a 24-hour strike instead.

The Kifissia-Piraeus electric railway (ISAP) and the tram are not in service between 8 a.m. and 4 p.m. on Monday.

A work stoppage from noon to 4 p.m. has been called for Tuesday on all three forms of fixed track modes of transport.

The public company responsible for managing the metro, tram and electric railway, Urban Rail Transport (STASY), is to argue in court on Monday that the strikes are “illegal and abusive” as they are not in line with labor regulations.

The unions are protesting the fact that employees have been inducted into the unified salary scheme for the public sector.

The general secretary for transport, Nikos Stathopoulos, said that while the workers have a right to protest, they must do so within the rules.

He also denied unionists claims that employees would lose as much as 50 percent of their salary.