BEIJING - More than 70 percent of urban Chinese singles getting nearer to their "expiry date" for marriage are in the grip of depression, according to China's first survey of their mental health.

"Many women who have reached a certain age like me need to make a lot of effort to ward off marriage pressure from our parents, as they keep bringing up the topic," said a 29-year-old woman surnamed Qi in Shanghai.

Qi, who has a good job in a foreign-invested enterprise, said she has seen an increased incidence of depression among the unmarried people around her.

"I admit that I want a husband, but I won't get married only for marriage's sake," she said.

These "leftover" men and women, as they are called in Chinese, are defined by the All-China Women's Federation as single women above the age of 27 and single men older than 30.

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The legal age for marriage is 20 for women and 22 for men.

The survey, which gathered information from more than 160,000 questionnaires, said only 25 percent of those women and men are satisfied with their current single lives. About 22 percent of them frequently feel lonely and 30 percent suffer from negative emotions like anxiety, weariness and frustration.

It also attributes the poor psychological and physical health of leftover men and women to sexual repression, misunderstandings of marriage, an excessive nightlife, delaying childbirth and pressures from parents and society.

Leftover women and men face greater risks of mental and physical problems, said Han Xiaohong, president of Beijing-based Ciming Health Checkup Management Group, which carried out the survey with the Chinese Medical Doctor Association.

According to the survey, 21.6 percent of the leftover women and men are subject to long-term sexual repression, while only 17.6 percent have regular sex partners. Visiting prostitutes and having multiple sex partners have become two main causes of sexually transmitted diseases, such as AIDS.

"The government should invest money to hold more matchmaking activities for these leftover people," said Wang Zhiguo, an expert with the marriage research center of baihe.com, one of the most popular matchmaking websites in China.

"For leftover people, they should also give themselves positive psychological suggestions, and enjoy their single lives before the right people appear," Wang added.