THIEVES have stolen a one-tonne rock from the National Rock Garden in Canberra.

The theft is believed to have happened on Thursday night.

The triangular rock is about one metre wide at its base, 75cm tall and grey and brown with stripes of white quartz.

Police say the thieves would have needed specialised lifting equipment to remove it from its perch on top of another rock.

Anyone with information about the theft or the rock's location is urged to contact Crime Stoppers on 1800 333 000.