The world’s largest recruitment agency, Adecco, has delayed publication of its financial results because of accounting problems – sending the company’s shares falling by 40%.

A statement from the Swiss-listed company said there were “material weaknesses” in internal controls in its North American operations.

And there were possibly problems in other countries that had not been resolved, the company admitted.

The firm has appointed an independent counsel to investigate and is not able to predict when the results, for the full year ending in December, will be published.

Adecco had previously promised to announce the results on 4 February.

Shares in the firm dropped as low as CHF 45.4 (£20) following the news, as traders panicked and sold their shares, fearing another corporate scandal.