The final touches are under way to fix one of the Hunter Region's "most notorious" bottlenecks.
Since ACCIONA Constructions Australia were named as the contractor of the Singleton bypass project in November, they have carried out geotechnical and utility investigations and additional site surveys.
These early activities on the $700 million project will inform the design before construction starts later this year.
Transport for NSW's environment team has worked with ecologists to oversee replacement hollows in trees to preserve wildlife habitats.
Federal member for the Hunter Dan Repacholi said the hollows would provide habitats for native animals including birds, gliders, possums and bats that might be displaced.
He said ACCIONA also undertook surveys of the Hunter River to ensure the protection of local aquatic species and river embankments.
"The Australian and NSW governments are committed to ensuring the furry, feathered, and arguably cutest residents around the Singleton bypass experience the best possible outcomes now and into the future," he said.
NSW Minister for regional transport and roads Jenny Aitchison said the bypass would divert around 15,000 vehicles a day and motorists would avoid five sets of traffic lights in Singleton's centre.
"The Singleton bypass will improve the lives of people living and working right across the Hunter region," Ms Aitchison said.
She said the project would improve safety and slash travel times for all users.
Federal minister for infrastructure and transport Catherine King said the project would "deliver economic growth" and support "more than 1,300 jobs during construction".
NSW legislative council member for the Upper Hunter Emily Suvaal said the federal and state government's collaboration on the project would set the Hunter "up for the future".
"This will ensure safer and smoother journeys for local motorists, visitors and our freight industry who rely on the New England Highway as an important link road every day," she said.
The eight-kilometre bypass was expected to open to traffic in late 2026.