Finnish foreign trade was crippled early Thursday after labour deal talks collapsed and the export-reliant country's stevedores went on strike, shutting all commercial sea ports.

National Conciliator Esa Lonka headed talks between the Transport Workers Union (AKT) and employers into the night, but no agreement was reached before the 6:00 am (0400 GMT) deadline given by the union for reaching a new collective labour deal, AKT said in a statement.

The strike is a blow to already recession-hit Finland, whose economy last year saw its biggest annual fall since 1918 as the global economic downturn dampened demand for key exports like paper and mobile phones.

Around 80 percent of Finnish foreign trade is transported by sea, according to the Confederation of Finnish Industries (EK), which says exports account for around 40 percent of Finland's GDP.

"The closure of ports means 160 million euros (219 million dollars) in lost export income and 120 million euros in lost imports per day," EK said on its website ahead of the strike. The figures are based on 2008 statistics.

The strike, initially scheduled to begin on February 19 but postponed by the labour ministry, includes some 3,100 permanent and 400 temporary stevedores who are union members, AKT said.

Last month, stevedores at several of Finland's key ports staged wildcat strikes, halting the passage of a large portion of freight in an effort to speed up the labour talks.

The strike follows a one-day work stoppage by Finnish road transport workers earlier in the week, and companies, including paper maker UPM-Kymmene, have said their production and deliveries are already suffering.