The acquisition would be MHI’s first outside Japan and it is seeking Japanese and US partners in the deal.
The company is focused on catering to the expanding Chinese energy market.
With Japanese demand for nuclear power construction falling, heavy construction companies Hitachi and Toshiba are also aiming to expand their nuclear power operations abroad.
Japanese companies are showing record levels of mergers and acquisitions, according to data tracker Thomson Financial.
Though a profitable business, MHI faces declining public works orders and narrowing profit margins from its shipbuilding, aerospace and power network operations.
Westinghouse’s parent company British Nuclear Fuels announced last week it was putting the company up for sale.
General Electric and French nuclear engineering group AVRA were also mentioned among the list of 15 potential buyers.
MHI’s bid could be hampered by growing US concerns over foreign interests in energy-related businesses. Its pursuit of a US partner is seen as politically motivated.
China's state-run oil company CNOOC announced a takeover bid for US oil and natural gas producer Unocal last month.
MHI and Westinghouse have had a business relationship for 30 years and have already bid to jointly build a nuclear reactor in China.
China’s demand for energy is seen as driving up costs of traditional sources and increasing the need for alternatives such as nuclear power.
Some analysts have speculated China itself might be interested in buying Westinghouse, but any bid was unlikely to be passed by regulators.
