Eli Lilly has become the latest foreign drugmaker to be accused of bribery in China, after Britian's GlaxoSmithKline and France's Sanofi were embroiled in similar controversy.

A whistleblower claimed in China's 21st Century Business Herald that the US drugmaker spent more than 30m yuan ($4.9m, £3.1m, €3.6m) on bribing doctors to prescribe its drugs over a period of one year from 2011 to 2012.

"In order to hit sales at rival companies and push the company's own products, bribes and special payments of all sorts were extremely common at the company. The level of the problem was just as bad as at GlaxoSmithKline," an anonymous former Eli Lilly senior manager, using the pseudonym Wang Wei, was quoted as saying.

In an emailed statement to Reuters, Eli Lilly said it was "deeply concerned" about the allegations.

"Although we have not been able to verify these allegations, we take them seriously, and we are continuing our investigation," the statement said.

Wang alleged that illegal payments were widespread at the company's China operations. He added that the company staff paid bribes to promote its two key insulin products in Shanghai and Anhui.

The company also provided illegal kickbacks to doctors via paid talks, conferences and other contributions, Wang claimed.

Novartis, Sanofi and GlaxoSmithKline

An unnamed whistleblower has also alleged to the 21st Century Business Herald that Swiss drugmaker Novartis AG paid bribes to doctors to boost its sales. The allegations prompted the company to launch an internal investigation into the matter.

Earlier in August there were reports that French drugmaker Sanofi is being probed by Beijing municipal authorities over bribery allegations the company said it is taking "very seriously".

Sanofi staff allegedly paid bribes totalling 1.69m yuan to 503 doctors at 79 hospitals in Beijing, Shanghai, Guangzhou and Hangzhou, in late 2007, to encourage them to prescribe Sanofi products.

In addition, British pharmaceutical giant GlaxoSmithKline has been facing investigation for suspected bribery and tax-related offences in China since early July.

China's Ministry of Public Security accused unnamed GSK executives of routing 3bn yuan in bribes to doctors through 700 travel agencies and consultancies over six years.

In connection with the allegations, Chinese authorities have taken several GSK executives into custody and claim a number admitted to criminal charges of bribery and tax law violations.

GSK also admitted some Chinese executives appeared to have broken the law, but CEO Andrew Witty said the head office had no prior knowledge about the wrongdoing.

China's National Development and Reform Commission (NDRC) is already investigating 60 foreign and local pharmaceutical firms over price-fixing and is yet to conclude the far-reaching probe.