The Supreme Court is due to rule this morning on whether victims can accept an award from the Hepatitis C Compensation Tribunal and later appeal the amount to the High Court.
The challenge, a test case backed by the Irish Haemophilia Society (IHS), relates to a man who contracted hepatitis C from infected blood products and who was awarded £125,000 (159,000) by the compensation tribunal in late 1997.
He signed-off on this payment before availing of a one-month period allowed for recipients to decide whether the amounts paid were acceptable, and without using that period to lodge an appeal to the High Court in the hopes of securing a higher award.
The result of the case is awaited by hundreds of other hepatitis C sufferers who also accepted awards from the tribunal, but now say the sums they received were not sufficient to meet the costs of ongoing medical care.
It could ultimately affect several thousand cases.
Other patients who rejected their initial awards and appealed to the High Court within the one-month period have seen their compensation payments significantly increased by the court.
The tribunal has paid out 319 million in initial awards to date, but this would increase substantially if victims time-barred from appealing were granted late access to the High Court.
Today's ruling comes at the end of a four-year battle by the unnamed man, who began his legal challenge in April 1999 and received a ruling in his favour from the High Court in July last year.
Both the Minister for Health and Children and the Hepatitis C Compensation Tribunal appealed that ruling to the Supreme Court, however, in a hearing that lasted several days last January.
The case centres on conflicting interpretations of the Hepatitis C Compensation Tribunal Act 1997, which lays down the one-month time barrier for appeals.
While the Minister for Health and the Tribunal argue that the Act must be literally interpreted, the IHS said the essential purpose of the Act was to provide "just" and "appropriate" compensation, and that this concern should override strict time barriers.
The Tribunal has so far made awards in 1,579 cases, but there are around 2,400 more being processed, and fresh claims continue to be received.
The remit of the tribunal was formally extended last year to compensate people who contracted HIV from contaminated blood, and the ongoing claims represent victims of both illnesses.