Shenyang's Yilishen Group claimed that investors could get rich by giving them money which they would use to raise ants.

These insects were supposed to be the main ingredient for a health tonic promising an aphrodisiac boost.

The tonic was promoted on television by Zhao Benshan, the country's most famous comedian.

But the group has twice delayed payment of dividends since October, fuelling panic and rumours that the government has frozen their funds.

'We strongly demand the government offer a way out for Yilishen!' read one of the banners carried by demonstrators.

Riot police were deployed to prevent protesters reaching the provincial government headquarters.

Yilishen survived several investigations in the past eight years and investors had previously received their dividends on time.

But some believe the ants to be a useless ruse for an illegal scam -- one that is now unravelling.

"It has been out there for eight years and the government has given the company and the manager so many honors," said investor Li Dechun.

"We thought there mustn't be any problem."

A spokesperson for the provincial government responded to the scandal by denying any responsibility.

That will be of little comfort to those who have lost their savings.

"Most of the investors are from the lower class of society," said Cong, a resident of Shenyang.

"Some have threatened to take more radical actions, such as blocking trains at the railway station."