A revision to China's Food Safety Law had its first reading on Monday and pledges tough sanctions for offenders, promising the strictest food safety supervision system.

The current law has helped improve food safety, but the situation remains severe, said Zhang Yong, head of the food and drug administration, when briefing the lawmakers at the bi-monthly session of the Standing Committee of the National People's Congress (NPC), which will run through Monday to Friday.

The existing system is not effective, penalties are comparatively light and it does not deter offenders, Zhang said.

A number of shocking malpractices, including injecting clenbuterol into pork, recycling cooking oil from leftovers in restaurant kitchens, selling pork from sick pigs, making medicine capsules with toxic gelatin and passing rat and fox meat off as mutton and beef have been headline news in China recently.

The latest case was use of illegal additives in growing bean sprouts, one of China's most popular vegetables. Police in east China's Shandong province seized nearly two tonnes of toxic bean sprouts last week.

The bill is considered a move to realize the promise the current leadership made at the third plenary session of the 18th Communist Party of China Central Committee in last November, which is to establish the strictest ever supervision system on food safety.

Through the law amendment, the country expects to impose the harshest civil, administrative and criminal penalties on offenders and toughest punishment on supervisors who neglect their duties, Zhang said.