Number of those injured in Australia bus crash rises to 25

Ten people have died and 25 are in hospital after a horrific bus crash in New South Wales' Hunter region overnight.

Report informs citing Sky News Australia that emergency services were called to Wine Country Drive near Greta about 11.30pm on Sunday after reports a coach had rolled.

NSW Police said initial inquiries indicated ten people were killed in the crash but the death toll could rise with 25 people taken to hospital.

The coach had been transporting guests from a wedding back to their accommodation.

A large-scale emergency operation involving multiple helicopters and several ambulances transported patients to John Hunter Hospital, Mater Hospital in Newcastle and Royal Alfred Hospital in Sydney.

The 58-year-old bus driver was taken to hospital under police guard for mandatory testing.

A crime scene has been established, which will be examined by specialist forensic police and the Crash Investigation Unit.

An investigation into the circumstances surrounding the crash is underway.

Family and friends began arriving at the scene early Monday morning as they try to make sense of the tragedy.

"It was a nice day, a pretty good wedding... fairytale stuff really...we got the news that there had been a crash, and we all started panicking," a guest told reporters.

Road closures are in place and Wine Country Drive remains shut between New England Highway and Bridge Street.

The northbound and southbound off-ramps from Hunter Express to Wine Country Drive also remain closed with motorists advised to take an alternative route.