Spokesman for the Suhada Port Workers Union Lal Bangamuwage told BBC Sandeshaya that the navy was sent to the harbour in order to stop workers from working to rule.

"The navy came to the tug boat section and forced workers to work," he said.

Spokesman Bangamuwage said, when notified by the membership, trade union officials had to intervene to stop the navy disrupting the work to rule.

He added that the trade unions have made a complaint to the police against the western region naval commander for threatening those on trade union action.

Workers in the public sector launched a three day work to rule campaign for higher pay due to them.

State power, water, oil and port workers stopped working outside assigned duties and set working hours from Wednesday after negotiations broke down as the government refused to meet their demands.