China Merchants may face regulatory hurdles if it does choose to issue A shares, since it already has subsidiary Shanghai International Port Group trading in that city.

Details of draft guidelines revealed last week covering the A-share issue of red chips - foreign-incorporated mainland firms - stressed that the focus would be on allowing the listing of companies that have no exposure to the domestic market.

But the conglomerate would meet the other key requirement - that red-chip companies must have a net profit of at least one billion yuan. Last year, China Merchants earned HK$2.5 billion.

Mr Fu's concern echoes statements made over the past week by an executive at China Life Insurance, tycoons Li Ka-shing and Lee Shau-kee, former US central banker Alan Greenspan, and sundry mainland officials.

On Wednesday, the China Securities Regulatory Commission ordered brokerages to educate investors about inherent risks in the stock market through posters, seminars and text messages, and by requiring new clients to sign a declaration acknowledging their awareness of the potential for a downside.

Mr Fu also said that to increase the company's focus on ports, it would consider offloading more of its non-core assets, including its 13 per cent stake in the Western Harbour Crossing tunnel.

He said that for the first four months of this year, the ports in western Shenzhen handled 16 per cent more containers than they had a year earlier.

The terminals at Shekou, which suffered a drop in throughput last year due to a Maersk line reshuffle of routes, handled at least 20 per cent more containers, he said.

Shares of the conglomerate closed at HK$34.30 yesterday, down 3.38 per cent.