As a drawn-out labor conflict at the Nordic region’s largest port escalates, some of Sweden’s largest exporters are warning they may be forced to find alternative harbours abroad to safeguard shipments.

Container capacity at A.P. Moller-Maersk A/S’ APM Terminals facility in Gothenburg has in the past six months dropped to 80 percent of the normal weekly level of 10,000 containers due to a conflict with the Swedish Dockworkers’ Union. It could drop to 40 percent in the coming days as APM plans a partial lockout in response to the industrial action.

The port handles about half of Sweden’s total container trade, so the stakes are high.

APM Terminals has warned of a partial lockout from May 19 until June 30, in response to blockades imposed by local 4 of the dockworkers’ union, which is seeking to become a party to a collective bargaining agreement that’s signed by the Transport Workers’ Union among other demands. During the lockout, the terminal will offer “only a limited daytime service,” according to APM.