A woman is in critical condition in hospital after she was hit by a bus and trapped for two hours on Wednesday afternoon.
The woman, who witnesses said was aged in her 30s, was taken to Royal North Shore Hospital with multiple critical injuries after the incident on Clarence Street about 3.50pm.
Office worker John Preston said he was eating a pie with a colleague when he saw the Sydney Buses vehicle run over the woman as it turned into Clarence Street from Erskine Street.
"The next thing I hear is a thump and a crunch and a never-ending scream," Mr Preston said.
"The bus driver didn't know he'd hit her. If we hadn't run out on to the street and told him, he would have kept going."
Inspector Norm Spalding, from the the Ambulance Service of NSW, said the woman was ‘‘extensively caught up’’ in the back axle of the bus.
Paramedics spent more than two hours trying to free her, finally succeeding about 6pm.
‘‘The rescue was slow and arduous and very difficult for those involved,’’ Inspector Spalding said.
‘‘In 37 years I would say this would be in the top five or six cases that I’ve been involved in in terms of delicacy, for want of a better word.’’
Paramedics had to climb under the bus at ‘‘considerable risk’’ to themselves to treat the woman, Inspector Spalding said.
It was terrible, absolutely terrible
"They were able to carry out some medical procedures under the bus and develop a rapport and stay with the patient."
The woman was conscious for most of the rescue.
Inspector Spalding also said the bus driver had received treatment.
The incident demonstrated the Sydney transport system's extreme sensitivity to anything going wrong near peak hour.
More than two hours after the collision, bus queues were banked up on multiple city roads and queues of commuters were struggling to get home.
Buses heading into or out of the city over the Harbour Bridge were delayed by up to 90 minutes, the Transport Management Centre said.
Mr Preston, who works on York Street, said the bus that hit the woman was empty.
He had rung triple-0 and gone to the woman's aid, along with other passers-by.
"She was still talking and wanted her husband called.
"It was terrible, absolutely terrible."
A worker in a building across the street said emergency services had been “giving the woman blood” and had jacked up the bus to free her.
Victor Guo was working at Pie Face when the woman was hit.
"I was making sandwiches out the back," he said. "I didn't see what's going on, I just heard screaming."
The incident is the latest in what has been a shocking start to the year on roads through Sydney and NSW.
Prior to the fatality at Monterey, 32 people had died on NSW roads in 2014, compared to 14 for the same period last year.