SYDNEY, June 13, 2023 (BSS/AFP) - A 58-year-old wedding bus driver is scheduled to appear in an Australian court Tuesday, charged with dangerous driving that caused the deaths of 10 guests.

Acting assistant police commissioner David Waddell said prosecutors will allege the man was driving "too quick" in what were believed to be foggy conditions just before midnight Sunday.

The bus carrying 35 passengers lost control on a roundabout and careened onto its side, killing nine people almost instantly.

Moments earlier, they had been celebrating the wedding of a young couple at the nearby Wandin Estate Winery in Australia's picturesque Hunter Valley wine region.

Another passenger later died in hospital.

Fourteen guests are still hospitalised, including two in intensive care.

The victims are aged between 20 and 60 years and suffered injuries ranging from lacerations to breaks and fractures.

Police say they are still piecing together their investigation.

But they have already charged the man, who is due to appear in Cessnock court after being denied bail.

Police have said that initial alcohol testing came back negative, but officers pointed blame at "erratic" speeding that some passengers had reportedly complained about before the crash.

"We've obviously now charged that 58-year-old bus driver, we've charged him with 11 charges," said Waddell.

"He entered that roundabout in a manner that was inconsistent with the conditions," he added.

"Obviously, the speed was too quick for him to negotiate that roundabout, causing the vehicle to fall on its left side, and causing those injuries."

The road crash was Australia's worst in 16 years and has caused widespread shock, with Prime Minister Anthony Albanese leading condolences to the victims.

"For a joyous day like that in a beautiful place to end with such terrible loss of life and injury is so cruel and so sad and so unfair," he said.