The two men appeared in the Perth Magistrates Court on Friday and pleaded not guilty to the charges, which arise from the long-running Project Wickenby investigation.
Ausdrill released a statement today saying the Commonwealth Director of Public Prosecutions had commenced proceedings to charge Mr Sayers with consipiracy to defraud the Commonwealth.
The charge is over matters arising from arrangements put in place by advisers engaged by Mr Sayers and a business associate at the time, and not associated with Ausdrill, the company said.
The Ausdrill board of directors said it had been fully briefed on the circumstances and remained fully supportive of Mr Sayers, who will continue in his role as managing director.
At 11:50AM WST, Ausdrill stocks had lost 4.7 per cent, to trade at $3.40.