Four people were taken to hospital after a hot air balloon carrying 18 people crashed near Cessnock, north of Sydney, early on Saturday morning.
The hot air balloon went down just after 6:00am at Camp Road Greta, about 21 kilometres from the town of Cessnock.
It is believed the balloon was attempting to land but struck a bush on the way down.
A 24-year-old woman sustained suspected back and spinal injuries while an 80-year-old woman suffered multiple fractures.
Ambulance Inspector Brian Knowles said the older woman was in a lot of pain with a broken leg and it took 40 minutes to get her out of the basket.
Two passengers were taken to John Hunter Hospital in a serious but stable condition and two to Maitland Hospital in a stable condition, a spokesman from operator Balloon Safari said.
Other flights in region cancelled this morning
There are four operators who fly balloons in the regions: Balloon Aloft, Balloon Safari, Beyond Ballooning and Wine Country Ballooning.
A man who was scheduled to take a flight in the Hunter region, near where the Balloon Safari flight crashed, contacted the ABC to say his flight had been cancelled on Saturday morning because the pilot had determined it was too windy.
Jonathan Steward and his wife was due to take a flight with aviation company Beyond Ballooning.
"Beyond Ballooning met their passengers this morning and decided to cancel the flight," a spokesman from Beyond Ballooning said.
Mr Steward said he was grateful the flight was cancelled.
Balloon picked up by the wind, operator says
Balloon Safari director Matt Scaife said the balloon made a "fast landing" after it was picked up by the wind, and the basket clipped a bush.
Mr Scaife said the injured 80-year-old woman had a prosthetic leg and was on the side of the basket that hit the ground hardest.
Three other hot air balloons in the area at the time made "routine landings", he said.
In a statement released by Balloon Safari, a spokesman said the balloon took off in "calm conditions" at 5:45am and flew for just over half an hour.
"During the flight the wind speed increased much earlier than was predicted by the Bureau of Meteorology," the spokesman said.
"The pilot decided to land at the first available landing spot. The balloon landed firmly and some injuries were sustained by passengers in the basket as a result."
The company extended its apologies on behalf of their ground crew and pilots to the passengers and involved.
Hot air ballooning has 'very good' safety record
The Civil Aviation Safety Authority (CASA) will be seeking a detailed report from the balloon operator and had the power to cancel the operating certificate from the company.
"We'll be looking to what exactly happened, whether there were any regulatory or safety issues which need reviewing and possible future action," CASA spokesman Peter Gibson said.
A number of Australians were caught up in a hot air balloon accident in Egypt last week that killed a South African tourist and injured 12 other passengers.
Despite this recent international incident, Mr Gibson said hot air ballooning had a "very good" safety record in Australia.
"Many hundreds of thousands of Australians take hot air balloons each year and there are very few serious accidents," he said.
"The last fatal accident in Australia during flight was in 1989."
The Air Transport Safety Bureau will also conduct an investigation into the accident.