The 40-kilometre expressway, a $1.65 billion extension of the F3, is expected to take up to 30,000 vehicles a day off the New England Highway and shorten by half an hour the drive south to Sydney or Newcastle and north to Tamworth.

The western section from Kurri Kurri to Branxton will be a 27-kilometre, four-lane road which should divert larger vehicles around Branxton, Greta and Lochinvar.

In the short term however, there will be some lowered speed limits and traffic delays.

From April 27, there will be short delays between 7am and 6pm on John Renshaw Drive, Buchanan, and the northern end of Stanford Road, Greta.

The speed limit will be reduced to 60km/h in both directions on Tuckers Lane and Camp Road, Greta, and Lovedale Road, Allandale, for one kilometre near the quarry.

Short delays and an extended 50km/h speed limit on Wine Country Drive, Branxton, have begun.

The Roads and Traffic Authority has urged drivers to be patient during the roadwork.

The federal government is providing $1.45 billion and the state government is providing $200 million towards the project, which will employ about 600 workers.

Federal Transport and Infrastructure Minister Anthony Albanese, NSW Premier Barry O’Farrell and Upper Hunter MP George Souris attended the ground-breaking ceremony last week.

“To achieve the full benefits of the expressway other works such as the bypass for Singleton and Muswellbrook, the rail overpass at Scone and new works on the intersection of the highway north of Willow Tree would be necessary,” Mr Souris said.