The company is in negotiations with union workers over the dispute, which has affected its Finnish Kirkniemi mill and its Maastricht and Nijmegen mills in The Netherlands.

Staff at Kirkniemi went on strike from 18-23 November over allegations of "serious safety issues", according to the International Federation of Chemical, Energy, Mine and General Workers' Unions (ICEM).

The union alleged that, following the redundancy of 63 staff earlier in the year, the remaining workforce has had to take on more duties and, as a result, occupational safety had been jeopardised.

However, a spokeswoman for Sappi refuted the claims. She said: "There were no real issues to go for the strike. The union claimed the redundancy program is proceeding too fast and there was a lack of knowledge and safety. 

"The consultation of Kirkniemi finished on 19 May 2009 and resulted in 63 job cuts. Kirkniemi's safety performance has improved and mill efficiency has remained at a normal level."

At Nijmegen, workers staged a 24-hour strike on 26 November and a 36-hour strike on Tuesday (1 December). Staff at the Maastricht mill carried out a strike from 27-28 November, with another due to take place from 2pm today.  

The strike action was in response to a row over the introduction of a new package of terms. Dutch unions issued a demand for a one-year wage increase of 1.5% on 24 November, according to ICEM.

The ICEM, which represents 800 workers at the two paper mills, has demanded the retention of annual reward days off for workers with long service careers.

However, Sappi said it has agreed a package that included a 1.5% salary increase for 15 months with unions and that this has not been accepted by staff.

It also included an agreement to open up a clause on paid days of leave for older staff.

The Sappi spokeswoman said the company was working hard to resolve the issue. "Effects on customers are being minimised," she added.

Sappi bought five European coated paper mills from M-real in 2009 and intends to close the Kangas mill in Finland by the end of the year, affecting up to 150 staff.

Elsewhere, Sappi Europe has put up the price for its Flexible packaging, Label papers and Release Liner grades by 5-7%. The new prices will be effective for deliveries as of 1 February 2010.

Sappi said the speciality sector faces a major squeeze on its operational margins because of the continuing rises in cost of raw materials.