The accident happened on Friday near the village of Medaki, in the Istria region, around 90 miles from the capital of Zagreb, when a van carrying a group of tourists veered into the path of a truck.

The Irish woman who was killed was in her 50s and is believed to be from Trim, Co Meath. It is understood that the seriously injured Irish woman was also in her 50s. She was brought to hospital in Pula suffering from multiple fractures and internal injuries.

Her condition is not thought to be lifethreatening.

It is believed that two Belgian tourists and the Croatian driver of the bus were also killed in the collision.

The tourists were on a day trip from the seaside resort of Pula to Porec at the time of the tragedy. They were driving across the border into Slovenia to see the famous caves at Postojna when the accident happened.

Postojna is on the main route south from Ljubljana and is part of day trips to the beaches of the Adriatic.

It is believed that the Irish tourists were independent travellers who had flown into Pula from either Britain or Madrid. They had booked their holiday with Fly Globe Spain and joined the tour company on arrival.

Yesterday's media reports suggested that three Irish people had been killed in the crash, and one seriously injured. However, a spokeswoman from the Department of Foreign Affairs said that Croatian authorities believed that only two people of Irish nationality were involved in the collision.

Croatia has become an increasingly popular destination for Irish tourists, with an estimated 40,000 people travelling there last year. It is also increasingly attracting young Irish backpackers who are travelling around Europe.

The country now features in the programmes of around 12 Irish tour operators.

Pula and Porec are particularly popular resorts for tourists, as well as the Dalmatian coast and the city of Dubrovnik.