China has ordered more accurate reporting of swine flu fatalities after a doctor renowned for helping expose the scale of the 2003 SARS outbreak said deaths were being deliberately underplayed.

The order issued late Thursday on the health ministry website appeared to be a bid to put a lid on suspicions of a cover-up along the lines of the Severe Acute Respiratory Syndrome outbreak, which authorities initially tried to hide.

Those suspicions were fuelled Thursday when medical expert Zhong Nanshan was quoted by a newspaper in southern China's Guangdong province as questioning the official nationwide tally of 53 deaths out of nearly 70,000 cases.

"I do not believe the current nationwide figures on A(H1N1) deaths," Zhong was quoted as saying.

Zhong's opinion carries weight because he became something of a national hero by openly defying the official line on SARS to help reveal the true extent of the illness.

Zhong told the Southern Metropolis Daily that authorities in some areas were under-reporting the number of swine flu fatalities to convince higher-ups they were effectively containing the virus.

He said this could include the failure to diagnose people who died from flu-like illnesses or conditions that may have been caused by swine flu, adding that the practice could lead to "even more severe consequences".

Zhong could not immediately be reached by AFP for comment.

The health ministry's statement said it "reaffirms that health authorities at all levels must conscientiously perform A(H1N1) prevention and control reporting work".

It quoted ministry spokesman Deng Haihua saying it was "strictly prohibited to conceal, omit, or delay reports of A(H1N1) deaths", adding that those who did so would "be held accountable".

However, it did not issue an outright denial of Zhong's comments.

China's official death rate is far lower than the global average, according to the World Health Organization, whose latest figures say 6,260 had died worldwide, out of 503,000 total cases.

The UN health body's China spokeswoman Vivian Tan told AFP that WHO did not "believe there has been deliberate under-reporting".

"But in China as in the rest of the world, it is nearly impossible to count every single case," she said.

"It's hard to know the real scale. This is not a problem unique to China."

Zhong's comments prompted a flurry of supportive entries in Chinese Internet portals - often the main outlet for free expression in China, where speech is restricted.

Some cited specific examples of cases where local officials refused to perform tests to confirm A(H1N1) in suspected sufferers, or charged exorbitant fees for such tests.

"I do not believe! False and misleading reporting is the specialty of local officials in China. Support Zhong Nanshan!" wrote one blogger on the popular Chinese portal Netease.

Chinese officials initially tried to cover up SARS to prevent political embarrassment, only coming clean after it began to spill into neighbouring countries.

China took aggressive steps to prevent swine flu entering its shores after it first emerged in the Americas earlier this year, including strict quarantine procedures.