Ferry services to the Greek islands have been disrupted after a seamen’s union went ahead with a strike that a court had declared illegal.

Union members blockaded the entrance to ferries in the main port of Piraeus, preventing anyone from boarding.

Hundreds of passengers with their suitcases gathered at the port, saying the ferry companies had not informed them of the strike, and heated arguments broke out between passengers and striking workers.

The union had declared a 24-hour strike to protest against a draft labour bill being debated in parliament, which workers say will erode their rights.

Other unions have declared strikes for June 10 as part of a general strike.

“Today’s strike, as you know, had been deemed illegal,” shipping and island policy minister Giannis Plakiotakis said.

“The choice of one union to move outside the legal framework is a wrong tactic, which turns against passengers and doesn’t serve the union movement.”

He said the ministry intervened, with the union eventually relenting and allowing passengers to board. The ferries set sail after several hours’ delay.