Hundreds of summer holidaymakers have been stranded during the peak travel week of the year after ash from Mount Etna forced the closure of Sicily’s primary airport for a fifth consecutive day.

Catania’s airport will remain closed until early Saturday, coinciding with the Ferragosto holiday marking the height of the Italian summer season, when millions head to coastal and mountain destinations, leaving cities deserted.

While Etna’s activity frequently interrupts flights at the airport, situated 30 kilometres (20 miles) south, the current closure represents the longest emergency since 2002.

"Volcanic ash can be a great risk for aircraft," said Boris Behncke, a researcher at the National Institute of Geophysics and Volcanology’s Etna Observatory. "It can be sucked into the motors, and force them to stall. This is why everyone is so very cautious with aircraft when there is a volcanic ash emission."

As Europe's largest active volcano, Etna's recent unrest is unusual for its persistent ash emissions. Northerly winds have carried light amounts of volcanic ash across to Malta and northern Africa.

"There have been many shorter interruptions — and stronger eruptions — over the past few decades, but this event is different because the ash emission from Etna’s summit has been much more persistent," Behncke said.

The closure has forced flights to be rerouted to alternative hubs, pushing up taxi fares and car rental rates, according to Italian daily newspaper Corriere della Sera. Consumer association Codacons announced it will file a complaint with Italy’s competition authority following complaints regarding price gouging.

Airport operator SAC stated 36 per cent of nearly 2,000 flights due to arrive in Catania between 6 and 12 August were cancelled, with over 600 diverted to Palermo, Trapani, Comiso, and Lamezia Terme. Departures briefly resumed over the weekend, but the airport was officially closed to both incoming and outgoing flights on Monday. Comiso was also briefly closed.

Italian train operator Trenitalia has added six services along the Palermo-Messina-Catania line to help ease travel pressure.

Italy's federation of travel agencies and tour operators has requested a task force to coordinate responses to Mount Etna’s disruptions, calling for a review into how airlines handled cancellations and passenger assistance.

"Operators are working around the clock to provide assistance, cancellations and alternative travel arrangements, but they cannot bear the burden of structural shortcomings and the management responsibilities of others,'' FIAVET President Gian Mario Pilieri said in a statement.