Another 6,000 staff at sawmills, plywood mills and other forestry plants had already planned to strike on Monday (27 January) according to Reuters, taking the total number of workers participating in industrial action to around 15,000.
Employers said they would respond with a three-day lockout of workers at 12 production sites from 10 February, unless a deal is reached by then.
The strikes are expected to affect the supplies and lead times of some types of paper.
The mediation of the labour dispute between paper union Paperiliitto and the Finnish Forest Industries Federation took place round-the-clock on Tuesday, but there was no resolution. Mediation will resume later today.
Paperiliitto said: “We and the forest industry tried to find an agreement between us, and the mediator was there to help. The mediator stated that it was not yet time for the reconciliation.
“The strikes and lockout will be terminated earlier than announced if a negotiated result is reached and accepted by the parties’ administrations as a new collective agreement.”
Reuters said that while labour unions have sought higher wages and fewer work hours, employers represented by the Finnish Forest Industries Federation have argued that the workforce is already too expensive compared with nations such as Sweden and Germany.
Jyrki Hollmén, labour market director for the Finnish Forest Industries Federation, told Printweek: “The forest industry wants to safeguard Finnish competitiveness and keep jobs also in Finland.
“However, negotiations with trade unions are stalling and strikes are currently paralysing forest industry production across Finland.
“The Forest Industries Federation, representing the employers, has for weeks been negotiating a package that improves cost competitiveness and provides conditions that are equal to those of other domestic export industries and key competitors.”
Companies affected by the shutdowns include UPM-Kymmene, Stora Enso and Metsä Board.
UPM commented on the strikes in its 2019 financial results, which were released yesterday.
The company said that as a result of the labour actions “production on all of UPM’s Finnish pulp and paper mills, label stock mill as well as plywood and sawmills has stopped”.
“UPM has prepared for the labour actions and strives to fulfil customer orders either from stocks or from the mills operating outside Finland,” it added.