Ryanair is being taken to court by Belgian national airline Sabena, which claims the Irish airline ran "misleading" and "offensive" advertisements in a Belgian newspaper last week.

The offending advertisement said: "Sick to death over Sabena's high fares? Low fares are coming to Belgium."

Ryanair announced plans in March to run 30 daily flights to Charleroi, near Brussels, making it the central hub for its continental European service. The no-frills Irish airline said it would cut Sabena's prices by between 80 per cent and 90 per cent. "I think we are certainly going to defend our advertising as both true and accurate, and we're going to defend that very vigorously," a Ryanair spokesman said.

Sabena wants the advertisements withdrawn and 10 million Belgian francs (€248,000) damages for any future violations.