According to authorities, at least ten people were killed and 25 were injured when a chartered bus transporting wedding guests slid off a ramp at a roundabout in Australia's New South Wales (NSW) state on Monday.

The tragedy happened around 11:30 p.m. on Sunday near Greta, about 180 kilometres northwest of Sydney in the Hunter district, known for its vineyards and wedding venues.

PHOTO | COURTESY Australian bus accident

"I understand they had been to a wedding together, and it's my understanding they were travelling together... presumably for their accommodation," NSW Police Acting Assistant Commissioner Tracy Chapman said during a televised media briefing.

At this point, Chapman believes it was a single-vehicle accident. She stated that police were still attempting to identify all of the passengers.

Footage broadcast on Australian television showed the bus resting on its side. According to officials, some people may still be trapped beneath the vehicle.

According to Chapman, the bus driver, a 58-year-old man, was arrested and anticipated to face charges in connection with the accident. He'd been sent to the hospital for mandatory drug and alcohol tests.

Heavy fog was prevalent at the time, but the reason for the road disaster, Australia's worst in over 30 years, had not been identified, according to Chapman.

PHOTO | COURTESY Australian bus accident

The two worst bus accidents in the country occurred within two months of each other in 1989, killing 35 and 21 people in NSW state. In 1973, eighteen passengers were killed when a tourist bus went down a slope due to a brake failure.

Premier Anthony Albanese offered his "deepest sympathies" to the families of those slain and injured.

"We've all experienced the joy of attending a wedding... they're some of the happiest times you can have." "It is cruel, sad, and unfair for such a joyful day in such a beautiful place to end with such terrible loss of life and injury," Albanese told reporters.