DESCRIBED by some analysts as ''one of the purest plays'' on the China telecom market, Champion Technology has established a strong presence on the mainland. Grossly under developed, China plans to invest in excess of US$100 billion to expand its telecommunications network between now and the end of the decade. The investment will cover telephones, cellular networks, data communications and other telecom-related services. Although still tightly regulated by the Ministry of Posts and Telecommunications the central government has plans to gradually liberalise the telecoms market. S. G. Warburg in its report, Telecommunications in Hong Kong and China: Opportunities for Foreign Investors in Two Exciting Markets, said: ''We see little chance anything meaningful will actually happen in the next two to three years, and in any case it is almost inconceivable the market will be opened up to foreign investors. However, this is not to say there are no windows for them. ''. . . For the next few years, we believe these opportunities will be limited to niche sectors suitable for small-to-medium sized telecom players that are more flexible in their strategy.'' Champion Technology has been quick to seize the opportunities with the first joint venture digital cellular phone service in China and a two-way satellite data service across the country. According to Warburg, over the next few years at least, Chinese paging will be the mainstay of Champion's profits. The company recently raised $460 million by issuing 100 million new shares at $4.675 each, a far cry from its initial price offering of $1.20 a year ago. One of Champion's chief assets is its Chinese-language paging service. The company has teamed up with a number of Chinese companies which have branches and affiliates throughout China and licensed to offer wireless telecom services in dedicated frequencies. In less than two years the company has completed 15 major projects with seven projects at various stages of pilot-run, installation and negotiation, with a further 15 projects under negotiation in cities around the country. The potential of the mainland market is enormous. Hong Kong with a population of six million has something like 1.2 million paging subscribers. Shanghai with a population of over 14 million has a penetration of just 300,000 subscribers and in Beijing (population 10.9 million), the penetration of pagers is even less at 200,000.