The worst monthly slump in Chinese stocks in two years wiped away more than $US34 billion ($45 billion) in combined net worth of the richest people in China and Hong Kong in June.

Of those 45 wealthy people on the Bloomberg Billionaires Index, more than 80 per cent lost money in June as the Shanghai Composite Index tumbled.

"The fortunes of billionaires are closely tied to the rise and fall of stocks," said Zhang Lu, a Shanghai-based analyst at Capital Securities Corp. "When the market is more unstable, like now, their fortunes go down."

Zhou Qunfei, chairman of Lens Technology, saw her wealth shrink the most among all Chinese billionaires. Her fortune shrank by $US4.8 billion in June as Shenzhen-listed Lens Technology tumbled 36 per cent. Zhou became the country's richest woman after the maker of mobile-phone glass covers went public in March.

The fortune of Wang Jing, chairman of Beijing Xinwei Telecom Technology Group, dropped from $US9.5 billion at the end of May to $US6.9 billion.

Billionaires who listed their companies outside China saw smaller declines.

Property tycoon Lee Shau Kee lost $US1.5 billion, paring his fortune to $US19.3 billion, after his Hong Kong-listed Henderson Land Development fell 6.7 per cent in June. Hong Kong's benchmark Hang Seng Index fell 4.3 per cent last month.

Richard Liu of US-listed online retailer JD.com and Robin Li of Baidu saw their net worth relatively little changed.