The chartered bus was supposed to be taking guests from a wedding reception at a wine estate to their accommodation.
At least 10 people have been killed and 25 injured after a bus carrying wedding guests crashed in Australia.
Police in the eastern state of New South Wales said the accident happened at 11:30 a.m. (13:30 GMT) on Sunday near Greta, about 180 kilometers (112 miles) northwest of Sydney in the scenic Hunter Valley wine region.
The coach went off a ramp at a roundabout on a foggy night, although fog has not been identified as the cause of the accident.
NSW Police Acting Assistant Commissioner Tracy Chapman said during a televised media briefing, “I understand they were at a wedding together, it’s my understanding they were traveling together … possibly to their accommodation.”
Two passengers were airlifted from the scene of the crash, Chapman added.
Television coverage showed the light-colored coach lying on its side after the crash, with a dozen emergency workers wearing high-visibility yellow vests working nearby.
The coach driver, a 58-year-old man, was taken to hospital where he underwent mandatory tests. He is expected to be charged in connection with the crash, police said.
“He is under arrest. He was the driver of a motor-vehicle collision that resulted in fatal injuries and charges are pending,” Chapman said.
The Hunter Valley and its vineyards are a popular location for short breaks and weddings.
A local mayor said the crashed bus was on its way to a wedding reception at a nearby wine estate.
“All Australians wake up to the tragic news of Hunter and send our deepest sympathies to the loved ones of those killed in this horrific bus tragedy,” Prime Minister Anthony Albanese said.
“It’s really cruel for a day of joy to end in such a devastating loss. Our thoughts are also with those who were injured,” he said in a message on social media.
The area is being examined by specialist forensic police and a crash investigation unit.
The two worst bus accidents in New South Wales were head-on collisions within two months of each other in 1989, which killed 35 and 21 people respectively. In 1973, a tourist bus plunged down a slope after its brakes failed, killing eighteen people.