SOUTH KOREA'S POSCO said on Thursday it was considering a rise in steel prices, easing fears that rising raw material costs will hit its earnings, and lifting its shares to a four-week high. The company, the world's fourth largest steelmaker, also said it may bid for Daewoo Shipbuilding, which analysts say could fetch nearly $5.1 billion, and was considering buying a stake in a Chinese firm. "We are considering raising steel prices but details in terms of the timing and the level of the price hike haven't been decided,' a POSCO spokesman said.