China has threatened to execute or jail for life anyone who breaks Sars quarantine orders and spreads the virus intentionally.
The punishments interpret existing laws
The Supreme Court and China's lead prosecutor set out the punishments in an interpretation of existing laws which regulate the containment of sudden disease outbreaks and the response to disasters, China's official news agency said.
The move comes days after China warned officials across the country that they would be punished if they covered up information about the spread of Sars.
China was criticised for failing to reveal the true extent of the crisis to its people and the world, after the pneumonia-like illness was first reported in November.
On Thursday China reported four more Sars deaths and 52 new cases, taking its total death toll to 271 and the cumulative caseload to 5,163.
Known death tolls:
Mainland China: 348
Hong Kong: 298
Source: WHO/local authorities
And the Sars emergency worsened in Taiwan, which with 26 new incidents saw its biggest one-day jump in fresh cases as the disease spread to the southern part of the island.
There have been about 7,700 cases of Severe Acute Respiratory Syndrome around the world, and more than 600 people have died.
But there was relief in Canada - which suffered 24 Sars deaths - after the UN health agency said the country had contained Sars, and lifted it from the UN list of affected areas on Wednesday.
Law 'may deter victims'
Human rights activists reacted with horror to news of China's latest crackdown, saying the death penalty ruling violated international human rights covenants.
"The measure is too extreme and the punishment too heavy," Hong Kong-based activist Frank Lu told Reuters.
Neighbouring Taiwan saw its biggest jump in cases
The World Health Organization said the draconian law could be counterproductive as it would deter possible Sars patients from going to hospital.
"There is a fine balance with this kind of disease where you need to isolate and quarantine patients, but if you are too heavy handed it may end up only stigmatising people," a WHO spokeswoman said.
The legal announcement reported by the Xinhua news agency, said that intentionally spreading disease pathogens that endangered public security or lead to serious injury, death or heavy loss of public or private property was punishable by 10 years to life in prison, or death.
Officials found guilty of negligently allowing the disease to spread face three years in jail; those making or selling fake drugs face 15 years to life in prison if their actions cause heavy losses; using violence to hinder aid workers could result in a three-year term.
Other crimes like taking advantage of an outbreak to raise the price of goods, misusing aid funds, illegally administering medical care, false advertising, false alarms and fabricating news of attacks can also lead to jail terms.
Fears for countryside
The crackdown responds to concerns that China's under-resourced rural health care system would struggle to cope with a serious Sars outbreak in the countryside.
The fact that at least 10% of cases in Beijing are among migrant workers has raised fears that the disease could spread within China's rural communities as workers return home.
Beijing hopes that the new rules, which will require any emergency to be reported within hours, will encourage authorities to respond as quickly as possible to fresh cases.
Officials said that China would invest more funding and resources in rural health care in the wake of Sars.
"China is a country with a big population. It's also a vast developing country, so problems of epidemics spreading is still very serious," said Qi Xiaoqiu, director of the Ministry of Health's department of disease control.
"Recently, we've asked various levels of government to step up prevention of other epidemics in addition to fighting Sars. This
includes our prevention and control work in Aids in China's