A “suspicious” fire in Plumpton destroyed 20 hectares of grassland last Friday.
Police believe a person, who has not been identified, started a fire and left it unattended.
The first CFA truck arrived about 1.15pm before another four CFA and five MFB trucks attended and brought the fire under control by 2.30pm.
Police are appealing to the public for assistance.
Anyone with information is urged to contact CrimeStoppers on 1800 333 000.
