London - Shares fell by more than 1 per cent, or 23 pence (0.38 dollars) to 1611.5 pence, in GlaxoSmithKline on Wednesday, after Britain's Serious Fraud Office (SFO) announced it was investigating it.

The London-based pharmaceutical giant has recently been accused by authorities in China, Iraq and Poland of bribing doctors to use its products in preference to others.

Two weeks ago Chinese police charged three of the company's top executives in China with bribery.

The SFO said on Tuesday it had launched a “criminal investigation into the commercial practices of GlaxoSmithKline and its subsidiaries,” adding that whistleblowers were “valuable sources of information” for it.

“We welcome approaches from anyone with inside information on all our cases including this one,” it said.

In a statement, Glazo said it was “committed to operating its business to the highest ethical standards” and that it would “continue to cooperate fully with the SFO.”

Under Britain's 2010 Bribery Act it is illegal for companies based there to bribe government employees, including doctors, at home and abroad. - Sapa-dpa