The headquarters of the Monaco-based oil company Unaoil and the homes of its executives have been raided by police in the wake of revelations in recent days that it has systematically corrupted the global oil industry.

In a statement, the Monaco government said it was helping British authorities investigate the "vast corruption scandal" revealed in recent days by Fairfax Media and The Huffington Post.

Police moved after Fairfax Media broke the story late on Wednesday that Unaoil and its owners, the Ahsani family, used multi-million dollar commissions to bribe corrupt governments in oil rich states to win contracts for large western firms such as Rolls-Royce, Halliburton and Australia's Leighton Offshore.