Witnesses called emergency services just before 7am with reports of a serious collision between a white dual-cab ute and the bike rider at the corner of Springhill Road and Keira Street.

Six ambulance crews were dispatched to the scene, including the NSW Ambulance Toll Rescue Helicopter with a specialist medical team.

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"Today we also had bystanders assisting with CPR and they should be commended for their efforts," NSW Ambulance Illawarra Inspector Terry Morrow said.

The cyclist - a man believed to be in his 40s or 50s - suffered head and chest injuries.

He was treated at the scene then eventually airlifted to St George Hospital by the Toll helicopter in a critical condition.

"When you arrive at a job like this, you are often confronted with a lot of trauma and distress," Inspector Morrow said.

"Our paramedics put their training to the test and did everything they could to provide life-saving treatment for the patient."

Meantime, the Inspector encouraged all members of the public to learn basic CPR, because "every minute counts ... between life and death".

Traffic was gridlocked during the morning peak hour around the intersection while a crime scene was set up by Wollongong police and forensic investigators.

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The driver of the ute was taken to Wollongong Hospital for mandatory testing.

Police are calling any witnesses or motorists with dash-cam vision get get in contact with them, or Crime Stoppers on 1800 333 000.

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