Chinese people are growing taller as the country becomes richer but they are getting fatter even faster, the government said.

Adult obesity rates reached 9.6 percent in 2012, more than doubling over a decade, the National Health and Family Planning Commission said in a report on national nutrition and chronic diseases. Those who were overweight went from 7.1 percent to 11.9 percent.

Among six to 17-year-olds the obesity increase was even more dramatic, more than tripling from 2.1 percent to 6.4 percent, while the proportion overweight went up by almost a third, to 30.1 percent.

"The problem of overweight and obesity is rising sharply as the dietary make-up has changed," Wang Guoqiang, a vice director of commission, told a press conference.

The average Chinese man weighed 66.2 kilograms (146 pounds) in 2012, extracts from the document posted online by the commission showed, up 3.5 kilograms over 10 years.

Women were 2.9 kilograms heavier on average at 57.3 kilograms.

"Smoking, excessive drinking of alcohol, insufficient physical exercises and unhealthy diet such as high salt and fat consumption are the main behaviour risk factors that trigger and worsen chronic diseases," Wang said at the briefing Tuesday.

"Pressures brought by the rapid development and transformation of the economy and society on people's life and work have also caused impact on health," he added.

The average Chinese man was 167.1 centimetres (5.48 feet) tall in 2012, the figures showed, and women's average height was 155.8 centimetres.

They were up just 0.4 centimetres and 0.7 centimetres respectively from 10 years earlier.

In comparison the Dutch -- the world's tallest nation -- average 184 centimetres for men and almost 171 centimetres for women.

The numbers made Chinese people "slightly shorter" than their neighbours in Japan and South Korea, the China Daily newspaper said Wednesday, quoting Liang Xiaofeng, deputy director of the Chinese Centre for Disease Control and Prevention.

A report published in The Lancet last year showed that 363,000 fatalities in China each year were linked to high body-mass index, an indicator for heart disease, diabetes and other ailments.