It was hoped the four would be the first of a string of China companies to list on the growing Canadian exchange, noted for floating less mature companies.

The Vancouver exchange, which aims to become the leading venture capital exchange in the world, has been keen to attract more companies from Asia.

So naturally the exchange was interested when it was approached by a financial services operation in Hongkong saying it had some mainland companies that could be interested in listing there.

But the creation of a powerful securities committee under the State Council has thrown a spanner in the works.

Beijing has expressed concern that uncontrolled direct overseas listings could undermine China's fledgling domestic stock markets.

Consequently, the new body is expected to put on hold some of the announced foreign-listing plans of mainland companies.

China Southern Glass, Gintian, China Bicycle and Shenzhen Vanke had the backing of the People's Bank of China, which was previously the mainland's sole stock market regulator.

''We are now adopting a wait and see attitude,'' said Mr Laundy, part of a 28-strong Vancouver business delegation to China, Hongkong and Taiwan headed by city mayor Gordon Campbell.

''Discussions between the exchange and China authorities are still under way.

''We have provided the information that was necessary for the negotiations to continue and we are going to wait and see what developments bring.'' There are already 60 companies with assets in Asia listed in Vancouver.

Most are from Hongkong, Korea and Taiwan, taking advantage of Vancouver's provisions that enable businesses to list at an earlier stage in their development than would be acceptable at home.