Malta's prime minister on Sunday promised a major clean-up operation after devastating gale-force winds caused major damage and disruption on the Mediterranean island.

Joseph Muscat said hundreds of people had called for assistance as the storm on Sunday damaged buildings and periphery walls and caused road closures in what some have described as the worst storm in living memory.

Parts of the island remained without power on Sunday as the strong wind reached gusts of up to 101 kilometres per hour.

Malta's main sewage treatment plant had to be closed and then evacuated after it became unsafe, Muscat told his political party radio One.

He also promised to help farmers through the EU's solidarity budget after thousands of crops were destroyed overnight.

The authorities advised people to stay indoors, with the damage forcing the closure of several roads and disrupting public transport. A number of flights were cancelled or delayed.