Adecco said its chief financial officer Felix Weber and the head of its North American Adecco Staffing business, Julio Arrieta, had resigned.

The Swiss-based group said its chairman, John Bowmer, would step into an executive role to lead the fight back against accounting problems.

Shares in Adecco, the world's biggest hiring firm, dived 10% on Friday.

Trouble-shooting

The share sell-off began after Mr Bowmer failed to satisfy investors' curiosity about the depth of the damage to Adecco's books.

"I assure you we will communicate and talk to people as soon as we can," Mr Bowmer said at a press conference called by Adecco to explain the board shake-up.

Adecco's admission of "material weaknesses" at its North American Adecco Staffing business triggered an investigation by the US Securities and Exchange Commission into accounting practices at the firm and wiped 35% off the value of its stock last Monday.

Adecco's board also appointed a second trouble-shooter; Philippe Marcel, chairman of its French operations, is to serve as "the board's special delegate in the US".

Addressing the problems

Adecco's board said it remained "strongly confident in the company and its future" and highlighted its strong cash balances of 900m euros ($1.5bn; �618m) at end-2003.

It issued a lengthy list of the problems unearthed so far at its North American unit, adding that some had already been corrected and the rest were being addressed.

The unit's problems included IT security, accurate payrolls and several issues involving the correct booking of sales. Adecco specialises in providing specialist temporary staff to service industries.

One reason why Adecco's shares plunged on Monday was that investors feared the audit problems might turn out to have seeped throughout the group.

Investigation continues

Adecco's statement acknowledged it has found "accounting, control and compliance issues in certain other countries".

But, it said, these countries together accounted for less than 10% of 2002 revenues.

Group Chief executive Jerome Caille remains in his job; he will concentrate fully on the day-to-day running of the business, Adecco said.