Although workers voted to open the factory, PAME activists were on Monday morning blocking access to the site, Eleni Katavati, who represents workers, told Skai.
Strike leader Giorgos Sifonios accused riot police for causing the problems. He said staff would be allowed to enter the factory after police had left the site.
Left-wing opposition parties have supported the steel workers' demands to limit layoffs at the factory and not introduce part-time contracts. They have accused the new conservative-led coalition government of acting like “gangsters.”