Levi Strauss & Co, hit by poor sales of its world famous blue jeans, said yesterday it will close 11 of its 22 North American manufacturing plants and lay off about 5,900 employees, or 30 per cent of its workforce in the region.

The family-owned company said the closures are part of a series of strategic steps by its American division to improve its competitiveness by moving its manufacturing operations overseas, where labour costs are lower.

The move comes a week after Levi, one of the world's largest brand-name clothing makers, reported its sales fell 13 per cent, from $6.9 billion to $6 billion last year, largely as a result of weak sales of jeans.