China's steelmakers may benefit from a possible spike in Japan's demand for steel and other building materials for its rebuilding efforts but opportunities are more limited in the replacement of Japanese steel exports, especially those of high-end steel products, analysts said Tuesday.

Japan, the second-largest steel producer after China, produced 109 million tons of raw steel and exported 43.4 million tons of steel last year. The massive earthquake that hit Japan's northern coast Friday has forced many steel mills, including Nippon Steel and JFE Steel, to shut down their facilities along the coast.

The export of thin and medium steel plates will see a dramatic fall, disrupting the supply-demand balance in the Asian market and pushing up prices, a report released Monday by an industry portal, mysteel.com, said.

The affected steel mills will suspend some facilities for at least six months and are expected to see a reduction in output of 2.5 million tons each month, or 30 percent of regular output.

"Japan's steel exports may fall and pave the way for Chinese steelmakers to fill the gap," Hu Yanping, a Beijing-based analyst with industry portal Custeel.com, told the Global Times. "Steel plates account for the major part of Japan's output of the metal, so exports of steel products such as hot rolling and medium steel plates from China are expected to rise."

Analyst Zhang Lin with the Beijing-based Lange Steel Information Research Center told the Global Times that bigger steelmakers in China will see big gains if they can meet the surge in demand.

"The reduction in Japan's steel output may open opportunities for China's top steelmakers to replace Japan's high-end steel exports, such as exports of silicon steel, as their production of these products has already reached the international standard."

Shares in China's steel mills were mostly up Tuesday, with Baosteel rising over 1.66 percent and Wuhan Steel up 5.98 percent.

However, Zeng Zhiling, director of JD Power Asia Pacific Forecasting, cautioned against being overly optimistic on big gains from the replacement of Japanese steel exports.

"Japan's steel exports mainly focus on the medium and high-end market, while China focuses on the low-end market. Even if China's top steelmakers have the chance to increase their exports of high-end products, time is still needed for these steelmakers to be recognized in the international market," he warned.