Valmet Automotive plans to cut 300 jobs in Germany because of dwindling demand for convertible cars, according to German union IG Metall.

The Finland-based company will eliminate all production jobs and some white-collar positions at a roof systems plant employing 400 people in Osnabrueck, western Germany, IG Metall’s regional director Stephan Soldanski said on Monday.

Valmet acquired the roof-making unit from German contract carmaker and cabrio specialist Karmann in 2010 after the company had filed for insolvency.

Valmet will either transfer jobs immediately to low-wage Poland or gradually phase out the positions through 2017, Soldanski said, citing a staff briefing by company managers on Monday.

Shifting production to Poland would allow Valmet to reduce production costs significantly. Labor costs in Poland’s manufacturing sector amounted to an hourly €6.65 per worker in 2012, about a sixth of the €36.98 in Germany, according to the Cologne-based IW economic institute.

Including job cuts in related trades, layoffs may exceed 900, Soldanski said.

Volkswagen currently builds the convertible version of its Golf hatchback at a separate plant in Osnabrueck employing 1,900 people, which also assembles Porsche sports cars.