The games are set to open in the Greek capital on 13 August.

Only 24 of the 38 Olympic venues have so far been completed and the finishing touches aren't expected to be put on the main stadium until 20 July.

The builders were among hundreds of thousands of workers who took part in a one-day strike on Wednesday.

The building firms and Olympics organisers say they are not worried about the strike as the time can be made up easily.

Overtime

"One day will not affect our work. Any delay can be covered with overtime and working on Sundays and holidays," said one building firm boss.