Thirroul's Keeley Gamble was cycling along Pioneer Drive near the intersection of Charlotte Harrision Drive about 3.45am on Thursday when a car hit her from behind sending her flying over the bike's handlebars and onto the road.

The driver did not stop and drove away.

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"I was lucky to only get bad grazes," Ms Gamble said. "My clothes are ripped and my shoes and watch are broken. The bike took most of the impact. It is a write-off.

"I have scratches and I'm sore but lucky there was no broken bones or anything worse."

Nearby residents heard Ms Gamble scream, came outside and called an ambulance and police as she sat on the side of the road in shock.

"Paramedics cleaned me up at the scene and I didn't need to go to hospital," Ms Gamble said.

The experienced rider hopes police can identify the car and driver after viewing CCTV footage from Woonona train station and surrounding businesses.

"It is scary to think that someone could leave someone else on the side of the road," she said.

"The driver didn't know if I was injured or dead.

"My fingers are crossed the police can find the driver."

Ms Gamble assumes the driver was drunk, on drugs or looking at their phone.

"The driver ran straight up the back of the bike," she said. "It could have been deliberate.

"It is scary to think someone would do that but you never know."

Ms Gamble was wearing bright clothes and had reflective lights.

She usually rides with a group of friends and was on the way to meet up with them when she was struck down.

Riding along Pioneer Road in the early hours of the morning is Ms Gamble's usual routine because she trains and competes in Ironman challenges.

"I saw the car behind me but I didn't think much of it until I felt it hit me straight on," she said.

"I usually ride Pioneer Road as opposed to the freeway because it is safer as there are less cars.

"There is no bike lane but it is a wide road with plenty of room to pass, especially when there are no other cars around.

"That's also why I ride at that time of the morning.

"I was shaken up and scared to go back on the road but I had to the next day because I was in a 200 kilometre bike ride."

Ms Gamble said she often copped abuse from passing motorists.

"It is disappointing drivers don't respect cyclists," she said.

"Sometimes cyclists don't follow the rules but sometimes drivers don't either.

"I am training for a sport and I feel unsafe on the road because drivers hate cyclists.

"I risk my life every time I go out on the road."

Wollongong police are urging anyone who may have witnessed the incident, have CCTV or dash cam footage or know any information about the motor vehicle or driver to contact them on 4226 7899.