Hyundai Motor, South Korea's biggest automaker, said Tuesday it would invest $270m to build a second engine plant at its US production facility in Alabama, as the company seeks to strengthen its position in the world’s top auto market.

The move fits in with plans by Hyundai and affiliate Kia Motors to double their market share in the US to 8.6 per cent by 2010. They are targetting combined sales of 1.65m vehicles in the US in 2010.