The 742-kilometre extension of the NSW Border Wild Dog Fence is underway.
The fence, designed to keep wild dogs off farming properties, will be the longest in the world once it's completed.
Deputy Premier John Barilaro and Agriculture Minister Adam Marshall turned the first sod on the project near Hungerford on Monday.
"The wild dog fence runs along the NSW and Queensland/South Australian borders and is critically important to landholders and local communities in western NSW and around the state," Mr Barilaro said.
"Once the extension is complete the NSW Border Wild Dog Fence will have more than doubled in length to 1325km, which will be the longest in the world and a titanic tool in the fight against pests and predators," he said in a statement on Wednesday.
Mr Marshall said the fence played a vital role in mitigating the impacts of wild dogs and was critically important to western NSW and the entire state.
"Wild dogs are a plague on primary producers and their local communities, causing more than $22 million in damages and lost production in NSW every year," Mr Marshall said.