Human Rights Watch on Thursday accused China of suppressing criticism of its response to the deadly novel coronavirus and said it had made the outbreak worse.

HRW chief Kenneth Roth also criticised the Chinese government's lockdown on various cities in an attempt to contain the virus as a "sledgehammer" approach.

"There have been big problems in China's response to the coronavirus that have worsened the outbreak," Roth told reporters in Geneva, although he also said China deserved credit for sharing the DNA sequence of the virus early on.

Roth pointed in particular to what he said was the "suppression" of reports on the virus in China during the early days of the outbreak, as well as subsequent efforts to stamp out criticism of its response on social media.

"There's no place for secrecy in fighting an epidemic," said Roth, who was barred from entering Hong Kong last month to present a report that accuses China of attempting to undermine the global system for protecting human rights.

"It's a time for total transparency, even if it's embarrassing, because public health has to be put before the preservation of a particular political power. Sadly, that is not Beijing's approach," he said.

Roth also criticised a series of city lockdowns at the epicentre of the epidemic in Hubei province in central China that have affected some 56 million people.

"Quarantines of this sort typically don't work. Quarantines, the kind that public health officials advocate, are much more targeted. They're aimed at people who have been identified as having the virus," he said.

"People need to be fed, they need to be housed, they need to get treatment and there are huge gaps in the Chinese government's response to these individual needs. This is not a rights-oriented approach to public health. This is treating public health with a sledgehammer," he said.

More than 28,000 people have now been infected across China and the death toll has soared to 563.

China's Supreme Court last month said an excessively harsh crackdown on online rumours during the outbreak had undermined public trust, in a rare rebuke of the police.

Authorities suspect the disease originated in a wild animal market in the city of Wuhan, and told the World Health Organization about the new virus on December 31.

A day later, eight people were punished by police after claiming online that Wuhan was in the grip of a fresh outbreak of SARS, which killed nearly 800 people in 2002-2003.

The group were reprimanded for "publishing or forwarding false information on the internet without verification", a police statement at the time said.

Authorities in Wuhan have already been criticised online for withholding information about the infection until the end of last year, despite knowing about the new illness weeks earlier. (AFP)