Police in the north-eastern Chinese city of Changchun have asked prosecutors to approve the arrest of 18 people at Changsheng Bio-technology Co Ltd, a vaccine maker at the centre of a safety scandal.

Key points: Police said Changsheng Bio-technology systematically falsified production and testing records

Police said Changsheng Bio-technology systematically falsified production and testing records President Xi Jinping ordered all relevant departments to investigate the scandal

President Xi Jinping ordered all relevant departments to investigate the scandal The company's chairwoman, three senior executives and two mid-level employees were taken in for questioning

China has launched sweeping spot checks on vaccine makers after Changsheng was found to have falsified data and sold ineffective vaccines for children, a case that has ignited public anger.

China's drug regulator has accused Changsheng of fabricating production and inspection records related to a rabies vaccine regularly given to infants.

In a brief statement, Changchun city police said their investigation had already "basically" found that criminality was involved in the company's vaccine production.

The 18 people they have applied to arrest include its chairwoman Gao Junfang, on suspicion of producing and selling substandard drugs, police said, adding their probe was continuing.

Parents are concerned their children received defective vaccinations. ( AP: Chinatopix )

Changsheng said last week Ms Gao, three senior executives and two mid-level employees had been taken in for questioning by local police.

Calls to the company seeking comment went unanswered. It is unclear if Ms Gao has been allowed to retain legal representation.

Prosecutors are unlikely to reject the arrest request.

The company has its main production base in Changchun.

China's cabinet investigation group found that Changsheng broke the law in manufacturing rabies vaccines, the state news agency Xinhua said on Friday.

Many mainland parents are bringing their children to Hong Kong for vaccinations following the vaccine scandal in China. ( AP: Kin Cheung )

The investigation group said the company had systematically falsified production and testing records to avoid regulatory scrutiny, according to Xinhua.

President Xi Jinping has ordered all relevant departments to investigate the scandal, which has triggered public outrage in what is the latest case of tainted medical products.

China's pharmaceutical industry has also been dealing with another case, the recall by Zhejiang Huahai Pharmaceutical of common blood and heart drug valsartan after an impurity linked to cancer was detected.

In a statement on Sunday, China's drug regulator said Huahai had completed the withdrawal in China of the raw materials used to produce the drug.

The drug has already been withdrawn in the United States and Europe.

Some netizens were critical of the quality of China's domestically produced vaccines. ( AP: Chinatopix )

Reuters