Swarms of locusts have destroyed crops and infested houses on the Italian island of Sardinia in what has been described as the worst such invasion in 70 years.

"We are walking on locust carpets", agricultural association Coldiretti Sardinia said in a statement.

The locusts have devastated animal grazing pastures covering more than 6,000 acres of land in the central province of Nuoro, between the small towns of Ottana and Orani.

Locusts are often seen in Sardinia during the summer but farmers said it was the worst outbreak since the end of World War II, and they said it was mainly due to odd weather patterns over the past two years.

"We had droughts in 2017 and a lot of rain in 2018, the ideal climate for locusts to emerge from fallow land and then move to cultivated fields to eat," said Michele Arbau of the agricultural association.

"There is nothing we can do about it this year," he told Reuters, adding that there was a risk of even worse infestations next year unless preventive action was taken now.

Mr Arbau added that it would be impossible to estimate this year's cost of the locust swarms until later in the season.