The Railways Ministry will buy 60 bullet trains from the Kawasaki-led consortium to run in China as early as 2008, the Yomiuri Shimbun said on its evening edition on Monday.
The orders will be placed as part of a project to increase the speed of China's trains, Kyodo News said, citing industry sources.
Kawasaki had no immediate comment on the reported deal, the value of which was not specified.
The report said China, looking to introduce high-speed trains, had chosen to buy half in the form of Japan's Hayate bullet train system and half from a system run by German engineering giant, Siemens.
Siemens said last week it had won a contract to supply 60 high-speed trains to China, and had put the value of its deal at $824 million.
The Hayate-model bullet trains, which run in northern Japan, were introduced in 2002 and operate at a speed of about 275km an hour.
State media in China has said Beijing wants to use foreign technology to set up a high-speed rail link between Beijing and Shanghai, which will help to overcome serious transport bottlenecks.
Japanese politicians and business leaders have aggressively courted their Chinese counterparts to win the contract.
The sale has also been politically sensitive at a time when relations between China and Japan are at their lowest level in decades, in part over memories of World War II.
Japan has reportedly offered to include the bullet train deal as part of its final low-interest loans to China.
Japan plans to end such loans - which have been seen as an indirect compensation for its wartime record on the mainland - before Beijing hosts the Olympics in 2008.
Japan's bullet train was introduced before the 1964 Tokyo Summer Olympics, showcasing the country's rapid technological advances since its defeat in World War II.