Reconstruction from the March 11 disaster that destroyed or damaged more than 150,000 buildings may boost volumes for dry-bulk shipping lines struggling with global overcapacity.

"The rebuilding process will need big volumes of material," Wei Jiafu, chairman of China Cosco (Holdings) Co., China's biggest dry-bulk operator, said Wednesday in Hong Kong at an earnings news conference. In the short term, the industry faces "severe challenges" because of the increasing size of the global fleet, he said.

Japan may increase imports of Australian iron ore and of logs and lumber from New Zealand and Malaysia after the March 11 tsunami devastated buildings in the Tohoku region. Following the Kobe quake in 1995, the Baltic Dry Index, the benchmark for commodity-shipping rates, surged 20 percent in three months after initially falling 6 percent in three weeks.

"In the medium to long term, it is an opportunity," Li Shaode, head of China Shipping (Group) Co., said at separate event. "Japan will definitely need to rebuild itself, and in doing so, it will need a lot of basic materials."

Shipping operations in Japan have so far been little affected since the quake, apart from the region directly hit by the tsunami, both Li and Wei said. The world's five biggest oil tanker companies have all said they will still travel to Tokyo Bay, home to Japan's biggest ports, and about 220 km south of the tsunami-damaged Fukushima No. 1 nuclear plant.

Of the world's 15 biggest container lines, only Hapag-Lloyd AG has halted services to Tokyo and Yokohama, Japan's busiest container ports. The others, including China Cosco and China Shipping, are maintaining operations.

Congestion in Tokyo, which delayed container shipments in the days after the quake, has now eased, said Huang Xiaowen, managing director of China Shipping unit, China Shipping Container Lines Co.

Vessels have been ordered by the government to avoid a 30-km exclusion zone around the crippled Fukushima No. 1 nuclear plant because of radiation discharge. This area doesn't contain any major container ports and doesn't impede key routes, Wei said.

"It has got no impact on us," he said. "We continue on the rest of routes there in Japan, such as to Yokohama."

Dry-bulk volumes may also benefit from rising demand for coal shipments in Japan as the nuclear plant shutdown causes power shortages and concerns about building new atomic plants, said Kang Seong Jin, an analyst at Tong Yang Securities Inc. in Seoul.

"This will help offset some of the overcapacity the industry is facing, but it won't be enough to resolve it," he said. "The pace of new deliveries has to slow before the bulk-shipping industry can recover."

China Cosco expects a 14 percent rise in global bulk capacity this year, compared with a 6 percent increase in volumes, according to its annual earnings statement. The Baltic Dry Index has dropped 48 percent in the past year.

Overseas ports have stepped up checks on containers arriving from Japan because of concerns about radiation plumes drifting out to sea.