The government will strengthen export control measures to help prevent the development of weapons of mass destruction, according to trade ministry officials.

Following a series of illegal export cases in Japan, the Ministry of Economy, Trade and Industry said it will conduct more snap inspections on traders and manufacturers, and urge research institutions to prevent exports of items and technologies that could be diverted for military use.

METI announced stricter measures after police raided Yamaha Motor Co. and several other companies earlier this year in connection with exports of products that could be used for military purposes to China and North Korea.

Specifically, the ministry will inspect 100 more companies later this year to check whether export controls are being followed and whether the firms properly categorize products that would require government license for shipping, the officials said.

METI, which has already probed 20 exporters this year, will start sending notices to targeted firms immediately before the inspections, the officials said.

It had been notifying companies a couple of weeks in advance.

The 100 exporters are among some 1,200 companies which have obtained comprehensive export licenses from METI.

The permission is issued for companies which frequently export items believed to have a low risk of being used for military purposes.