It is expected that around 80% of inbound and outbound foreign trade will cease while the strike, which began on 4 March after talks between union officials and port operators collapsed, continues.

Manufacturer Stora Enso has now closed several of its machines – its Anjala PM2 on 10 March, Oulu PM6 on 11 March, as well as its Varkaus PM2 and Oulu sheeting plant on 12 March. Oulu PM7 and Veitsiluoto PM1 and PM5 were closed today.

Meanwhile, UPM has been forced to close its Rauma paper mill due to the strike and all of the mill's four magazine paper machines have shut down.

Preparation for further machine line shutdowns at the group's other mills in the country is ongoing, the company said.

In addition, Sappi Fine Paper Europe stopped production at its Kirkniemi paper mill on 4 March.

The strike is another blow to the beleaguered Finnish paper industry, which has been hit by overcapacity and raw material price increases over the past few years.