Investigations into so-called "pick-me-up" schemes used to make donations to political parties resulted in payments of £135,000 to the Revenue Commissioners in 1998. The schemes are still under investigation and further payments are likely.

The Revenue's chairman, Mr Dermot Quigley, said payments up to the end of 1998 were "payments on account" - where defaulting taxpayers make payments before their exact tax liability has been decided in order to avoid additional interest charges.

The "pick-me-up" arrangements, identified during 1998, involved the bill for goods or services purchased by a political party being invoiced by the supplier to another trader wishing to aid the party. That trader then paid the bill.

These payments were not tax-deductible for the company or individual making the payment, VAT could not be reclaimed and invoices issued were not in accordance with legal requirements. According to the Revenue Commissioners' annual report, "while some taxpayers treated their payments correctly for tax purposes, others did not".

Mr Quigley said some schemes were complex, adding that there were a lot of people to be interviewed. Payments made so far have come from "individuals and suppliers", he said.

"We are pursuing it and we will report again. We are anxious to give as much information as possible."