The Finnish paper manufacturer has now set a minimum price increase of €50/tonne (£45) across all deliveries invoiced from 15 April.

Metsä Board marketing director Simon Guffogg said: "This will give purchasers and others an immediate quantitative snapshot of what to expect at the minimum."

Earlier this month, Metsä Board announced its intention to increase the price of its uncoated woodfree paper ranges, although the proposal was in the early stages, to "draw attention to the current situation we face and alert the industry" according to Guffogg at the time.

This was despite the fact that in its 2012 financial report, published just weeks before the first whispers of a price rise arose, Metsä Group said that "no significant increases" in the price of its uncoated paper, linerboard and folding boxboard were likely to come into effect in the foreseeable future.

Guffogg said: "The statement is true for the first quarter [2013], however things develop quickly, [there have recently been] pulp cost increase announcements."

Metsä Board vice president of sales and marketing Mattias Kronberg added: "We need solid pricing policies to offset continued cost increases in raw materials, energy and transportation. This means that we must now raise prices in order to keep pace and retain a viable margin balance."

The price rise proposal follows similar announcements from European paper manufacturers Sappi and Arjowiggins earlier this year, which also blamed rising costs in the factors mentioned by Metsä Board.