April 20 - Finnish retailer and department store group Stockmann warned on Wednesday it would post an operating loss for the first quarter due to weak sales at its fashion chains.

Stockmann department store in the centre of Helsinki, Finland

The January-Martch operating loss would be around 30 million euros ($42.95 million) and results would fall year-on-year in all business divisions, Stockmann said.

"The slow market development, particularly in the affordable fashion segment in which Stockmann Group's fashion chains Lindex and Seppala operate, has resulted in lower sales volumes than expected in the first quarter," it said in a statement.

Stockmann reiterated its full-year 2011 guidance for revenue growth and a higher operating profit than last year.

(Editing by Louise Heavens)