Komatsu Ltd., the world's second-largest construction machinery maker, said Japan's bid to rebuild from its worst postwar disaster is spurring demand at home amid slumping sales in China, its biggest market.

Domestic orders have risen more than 30 percent in April-June from a year earlier, Chief Executive Officer Kunio Noji said in Tokyo. Sales in China, which fell about 40 percent over the past two months, may not revive until the Lunar New Year in January, which kicks off the peak season, he said.

Sales of excavators and wheel loaders are likely to grow for the next three to five years as Japan spends an estimated ¥16.9 trillion to rebuild bridges, roads and buildings destroyed by the March 11 earthquake and tsunami.