Thieves have stolen around 1,500 kilograms of avocados from a property in South Australia's Riverland region.

Police say the fruit was stolen sometime between late August and early September, with around 20 trees on the property being stripped of avocados.

Local growers say they're not surprised by the theft.

Avocados currently retail for anywhere between $2.50 and $4 each, and thefts have occurred in the past.

The tri-state director of Avocados Australia, Robinvale producer Barry Avery says he caught thieves in his orchard just last week, and Waikerie grower Colin Fechner says a few years ago a similar quantity of fruit was stolen from his trees by 'itinerant pickers'.

Mr Fechner says it would take about eight hours for one person to pick 1,500 kilograms of fruit. He expects a group of thieves were probably involved with stealing the avocadoes from the Barmera property.

Stolen fruit is often sold at farmers markets.

Avocado crops in the Riverland and Sunraysia regions are currently being harvested, and growers have already faced challenges posed by January's intense heatwave and recent severe frosts.