A business lobby group has warned of an upsurge in online fraud and so-called phishing scams aimed at businesses, including fake emails purporting to be from the Revenue Commissioners requesting financial information to process tax.

The Irish Small and Medium Enterprises Association said it had received an increase in complaints and warnings from members in the last two months, with many concerning international director scams.

"These scams are particularly prevalent during the holiday periods as fraudsters are aware that, in many cases, senior management may be out of the office, leaving more junior staff to take decisions," said Isme chief executive Mark Fielding.

Isme is warning members to be careful when dealing with all unexpected invoices.