Foreign vehicle makers will soon be allowed to joint the Japan Automobile Manufacturers Association (JAMA), local media reports said.

A revision of the rules has been likely since General Motors applied for membership last year.

JAMA would previously only admit members which manufacture cars in Japan and GM, so far, does not. Its part-ownership of Isuzu and Suzuki did not count.

However, now that Suzuki is helping GM develop and build make the YGM-1, a new entry-level Chevrolet model for Asian markets, JAMA changed its mind.

A foreign car maker can now join the organisation if its local subsidiaries include car manufacturing as a line of business in their company constitutions; its designs and develops cars under its own or a parent company's brand and its currently produce cars – or assigns production to an affiliate company – in Japan.

GM can tick all the ‘yes’ boxes because it was the leading Japanese car maker until the second world war so manufacturing is in its constitution. Affiliate Suzuki is helping to develop the new Chevrolet and will make it.

Some reports from Japan say that certain JAMA members wanted to admit GM only as an ‘observer’ but the organisation’s president (and Toyota chairman) Hiroshi Okuda overruled that idea.

Okuda has pledged to make JAMA more open and to increase its international contacts.

He told a Japanese press conference that more foreign car companies are likely to apply for membership as their ownership of Japanese firms increases.

Applications should be handled fairly to avoid JAMA being labelled protectionist, Okuda said.