A POPULAR and on-going debate in Hongkong is whether the development of ports in southern China will pose a threat to Hongkong port. Most analysts agree that the Chinese ports will only become a threat when the mainland has fully developed its internal infrastructure. As long as the internal road network is not well connected, Chinese ports such as Shekou, Yantian, Chiwan, Mawan, Huangpu and Zhuhai, will play only a complementary role to Hongkong. But Shenzhen's local government plans to increase capacity to 20 million tonnes with 100 berths by 1995, and 40 million tonnes with 134 berths by the year 2000. Analysts fear that if this becomes a reality, coupled with Hongkong's terminal development, there will be over-capacity. Among southern China's ports, Shekou has drawn much attention by attracting shipping lines such as American President Lines and National Saudi Arabian Lines to its berths. This month, P & O Containers started a regular international commercial shipping service to Shekou, calling it a ''repositioning exercise''. ''P & O is starting this service as costs involved in cross-border operations are high and delays are considerable,'' said Mr Harry Feasey, Swire Shipping (Agencies) regional marketing manager for North Asia. But whatever reasons shipping lines give for starting a direct service to Chinese ports, the result is the same: fewer boxes will come to Hongkong. Meanwhile, shipping lines are watching all developments closely, including Wharf and Hutchison Whampoa's investment to develop Yantian port. The move has fuelled speculation that terminal operations in China are far more viable than operating out of Hongkong, putting a question mark over Hongkong's plans to develop Terminal 10 on Lantau Island. Meanwhile, the future of container Terminal 9 is in doubt after it was dragged into the Sino-British dispute. The Director of Marine, Mr Tony Miller, has said that the development of ports in southern China poses no threat to Hongkong. His argument is that, as southern China's economic growth forges ahead, more and more cargo will be generated and there is only so much that the territory can handle. Anything more than that would mean trouble for Hongkong, which is already facing congestion problems during the peak months in the middle of the year. Port Development Board secretary Mr Tony Clark said recently that he expected Hongkong port to be congested this year until the first berth of Terminal 8, which is currently under construction, came on stream in August. Whatever boxes Hongkong's terminals could not handle could be taken on by mid-stream operations, he said. Last year, Hongkong port regained the title of the world's premier container port, which it lost to Singapore in 1990, after handling nearly eight million TEUs. Judging from last year's container throughput growth of more than 29 per cent against 1991, Hongkong should grow by at least 20 per cent again this year or about 1.6 million TEUs - a massive amount by any standards. Last year, the mid-stream facilities grew by more than 60 per cent and the river trade by 379.9 per cent. The predictions are that, as the increased container throughput clogs up at the border crossings, resulting in delays, more of the container traffic is going to find its way to Hongkong by the river trade barges.