Nippon Yusen K.K. and Mitsui O.S.K. Lines Ltd., Japan's two largest shipping lines, boosted earnings as higher demand for coal, iron ore and grains more than offset hikes in fuel.

Nippon Yusen boosted net profit 55 percent to ¥44.4 billion in the three months to June 30, the company said in a statement Friday. Mitsui O.S.K.'s profit jumped 63 percent to ¥55.3 billion, it said separately.

The two companies are benefiting from China's demand for iron ore to fuel a building boom before the Beijing Olympics start next month. Stronger earnings at the two Tokyo-based companies contrasts with a 17 percent drop in profit for Kawasaki Kisen Kaisha Ltd., which gets more of its sales from shipping containers.