It was not clear if the firms will shift completely or in part from China.
One of them, the Hoya Corporation, which produces hard-drive components, is expected to move to both Vietnam and Laos.
Jetro said the Japanese government will give each company 100 million ($930,000) to five billion yen ($46.7 million) for the move.
Apart from the 30 companies set to move to Southeast, 57 others including Iris Ohyama Inc., a private face mask maker, and Sharp Corp., are set to be subsidized to the tune of 57.4 billion yen ($536 million) for the shift from China, Bloomberg reported, citing Japan’s Ministry of Economy, Trade and Industry.
The subsidies are part of a plan to diversify Japan's supply chains outside of China that was unveiled in April. The government announced then it has earmarked a 243.5-billion-yen stimulus package to help Japanese companies move production out of China.
Japan is the second economy after Taiwan that has made a specific move to diversify its supply chains and reduce reliance on China.
Taiwanese authorities last year supported companies with land, power, water, capital and tax breaks to lure them back home.
Japan was Vietnam’s fourth largest investor in terms of registered capital last year after South Korea, Hong Kong and Singapore.
By Quynh Trang, Minh Nga