The Serious Fraud Office in Britain has begun a criminal inquiry into GlaxoSmithKline over its commercial practices.
It is unclear whether the investigation centres on bribery accusations by China against the giant pharmaceutical company.
GSK refused to comment on whether the SFO investigation was connected to any specific incident.
In a short statement, the company said it was "committed to operating its business to the highest ethical standards".
The company, which is one of the largest in Britain, is also facing inquiries into similar accusations in Poland and Iraq.
Last July, China announced it was investigating the company and four Chinese GSK executives werer detained.
The BBC reports GSK has previously confirmed that it informed the SFO, as well as the US Department of Justice and the US Securities and Exchange Commission, about the Chinese investigation.
GlaxoSmithKline had its origins in New Zealand at Bunnythorpe in the Manawatu in 1873.