The EU's top court has issued an opinion in favour of a Dublin woman who took a case against Ryanair for its failure to pay her for expenses occurred when her flight was delayed during the disruption caused by the Icelandic volcano in 2010.

Denise MacDonagh took Ryanair to the European Court of Justice after the airline refused to refund her €1,129 in expenses incurred after her flight from Faro in Portugal to Dublin was held up by nine days due to the volcanic ash cloud which brought chaos to European airspace.

Ryanair had argued that the effects of the ash cloud constituted extraordinary circumstances and, as such, EU passenger rights should not apply.

This evening Ryanair issued a statement saying it noted that the Advocate General's opinion is not binding on the ECJ, hoping that the Court will side with the airline in its final decision.

It also said that this was a test case, that all other claims have been settled and there is no potential or retrospective financial liability to Ryanair.

This morning the Advocate General of the Luxembourg-based court issued an opinion that Ryanair was still obliged to meet the accommodation, food and other needs of passengers even in extraordinary circumstances.

The opinion held that while the obligation to pay compensation per se was not applicable because the extraordinary circumstances could not have been avoided, the obligation to provide care to passengers was "especially important and essential" if their flights had been cancelled.

The opinion also held that it was because of the very lengthy nature of the disruption that care was essential.

A limitation of the the obligation would, he argued, "deprive the EU legislation of its effectiveness".

It was not disproportionate for the airlines to be obliged to provide such care since they were free to pass on the resulting costs to passengers through ticket prices, the Advocate General said.

This had already been done by Ryanair, he argued, when it introduced a special levy in April 2011 which was specifically related to the Icelandic ash cloud crisis.

The opinion held that airline passengers affected by such circumstances were in a situation which was "objectively different" from the situation of passengers using other means of transport.

The full judgement will be announced later in the year. In 80% of cases the Advocate General's opinion is confirmed in the full judgement.