Wang said after they returned to their hotel, they stayed inside for three days until they could get plane tickets back to Beijing.

Since the exhibition was aborted before it could open, Wang's company's expenses for the exhibition, about 120,000 yuan ($20,000) cannot be recovered.

"We planned to expand the Vietnamese market with this exhibition. Now that it is so dangerous for Chinese, we decided to give the market up," she said.

Vietnam riots 'threaten ties and investment'

Top 10 trading partners of the Chinese mainland

Because of the relatively low costs, Guangdong authorities had encouraged businesses to invest there, said Ma Yao, a researcher with market research firm CI Consulting.

Companies in Shenzhen, including Huawei Technologies Co, ZTE Corp and Han's Laser Technology Co, have invested in 22 projects in Vietnam, with a total investment of $420 million.

But the riots there will affect the enthusiasm of Chinese businesses to invest in Vietnam, Ma said.

The worry of Chinese investors will only be eased if the Vietnamese government offers a sufficient guarantee and properly addresses the case, he said.

Meanwhile, Huawei and ZTE, two telecom equipment giants of China, said they have no intention of stranding their employees in Vietnam, Shenzhen Evening News reported on Tuesday.

According to ZTE, the company had transferred the employees in other cities of Vietnam to the capital Hanoi as of last week, but their projects have been operating normally.

Sources from Huawei said the company would not make special arrangements to relocate workers.

TCL Corp, one of China's largest household appliance makers, said on Monday its television factory in Vietnam had not been affected and that the plant had taken security measures to safeguard its personnel and property.

The plant in Vietnam has a capacity to produce 600,000 TV sets a year, accounting for a small portion of the company's total.

Yan Yiqi in Ningbo, Zhejiang contributed to the story.