Seventy-six ships and four barges are now blocked at the port because of the strike, the port authority said in a statement, down from 80 ships and four barges Tuesday.
The port's CGT unions have also called on workers to strike Thursday, as part of the day of national protest against pension reforms, the port said.
Workers at the oil terminals have been striking to protest against a range of issues, including the government's planned pension reforms and changes to the way the port is run.
Waiting are 37 oil tankers, along with 20 tankers of refined products, six chemicals ships and 13 gas vessels, the authority said.
Seven more ships were also detained outside the port, the statement said.
As well as serving the several refineries around Fos-Lavera, the port serves the South European Pipeline. That pipeline supplies the refineries, and a petrochemical plant, located along the inland axis from Fos to Karlsruhe, Germany.
The pipeline transports about 23 million metric tons a year, or more than 30% of the crude oil transport in Europe, according to its website.