THE main building of the heritage-listed Avoca Homestead complex at Wentworth was severely damaged by fire last week.

Located on Low Darling Road, the building caught fire about 9pm on Tuesday last week.

A statement from the NSW Rural Fire Service said seven fire trucks and 25 firefighters from the RFS and Fire and Rescue NSW took hours to control the incident.

"Upon arrival, the building was found partially involved, with fire involving approximately 50 per cent of the late-1800s building," said NSW RFS Lower Western district co-ordinator inspector Justin Ryan.

"Two occupants had safely evacuated the building with the assistance of neighbours, suffering only minor injuries.

"The building was a significantly solid wooden structure given its age, with the fire taking several hours to bring under control.

"Fire crews were able to save a significant section of the main homestead building, along with numerous personal effects and nearby outbuildings.

"Crews remained on scene throughout the night and into the following day, maintaining watch and extinguishing flare-ups."

Built between 1871 and 1879 near the Darling River, the site has changed hands many times during the last two centuries, including to the ownership of a member of the Chaffey family.

In 2000 Ian and Barbara Law purchased 40 hectares containing the Avoca Homestead and outbuildings site and in April 2016 the complex was added to the NSW State Heritage Register.