Sunday (10 April) will mark day 100 of the strike, which started on 1 January and is affecting UPM’s Finnish pulp and paper mills.

UPM last officially updated on the situation on 31 March, when it was announced that there would be a further extension of two weeks – to 30 April, that negotiations between the union and UPM businesses were continuing intensively, and that the conciliator had submitted a settlement proposal in the negotiations between UPM Pulp and the Paperworkers’ Union.

The parties must state their position on the Pulp proposal by 14 April.

UPM has still not commented officially on the likely financial impact to the group but the union believes the strike is costing the business around €20m (£16.7m) a week.

The strike involves UPM Pulp, UPM Biofuels, UPM Communication Papers, UPM Specialty Papers and UPM Raflatac units in Finland.

Around 200 union members continue to work at the pulp and paper sites on tasks deemed critical to society, such as power plants and water treatment facilities.

The strike is causing serious issues with the availability of graphic and label papers across Europe, and global trade unions have called on UPM’s major shareholders to put pressure on the €9.8bn group to resolve the situation.

Last week, label industry body FINAT sent a letter to the Belgian cabinet taskforce on Agrofood Supply to appeal for a European approach to the current supply chain distortions, in particular the paper shortage. FINAT said the situation had been “aggravated” by the continued UPM strike.

Finnish trade publication Print&Media reported today (8 April) that the shortage of labels is now escalating in Europe due to the UPM strike. It said UPM Raflatac is the largest supplier of label backing papers and that other suppliers are not able to completely fill the gap.

The article also said that UPM’s company communications had been speaking to Finnish business newspaper Kauppalehti about the situation.

UPM is quoted as having told the newspaper that UPM Raflatac has provided customers with alternative materials and sourced alternative raw material suppliers globally during the strike, but that these measures have not been able to fully ensure the availability of products.

The normalisation of the supply chain for the production and labelling of raw materials after the strike will take “several months”, UPM is said to have added.