Communities in the Great Southern have been asked to report any sightings of hares to the Department of Agriculture and Food.
Spokeswoman Marion Massam said a photograph was handed to the department late last year of a hare shot at Lake Norring near Wagin. There have been other general reports of hares near Williams, Narrogin and Kojonup.
"We sought further input at Wagin Woolarama this month, and received a further report there," Ms Massam said.
"Hares are declared pests in Western Australia, and currently there are no known wild populations in this State.
"It is important for the department to know of any sightings quickly, if we are to continue to protect our agricultural industries and native wildlife from this exotic pest."
Ms Massam said it was illegal to import or keep hares in WA. Any found in the wild were removed.
"Privacy laws ensure any reports to us will remain confidential," she said.
Hares are similar in appearance to rabbits, but can be distinguished by their larger size, proportionally larger hind legs, black-tipped ears and their characteristic loping, tail-down gait when disturbed.
Sightings of hares should be reported to the local department office.