The incident involved cyclists from the long course at George's Plains with riders suffering a range of injuries from minor to serious.

Mayor of Bathurst, Graeme Hanger said St John Ambulance were first on the scene with NSW Ambulance activating an emergency response after receiving a 000 call from commissaries following the riders.

A spokesperson for NSW Ambulance said the 000 call came through just after 10.35am, with seven road units and two air rescue units sent to the scene.

The group of riders were heading south towards Trunkey Creek Road, on Cow Flat Road, when they became caught up and came crashing down. It is estimated the riders would have been travelling between 35km an hour and 45km/h when they came off their bikes.

Initially it was thought only two riders were injured, but that was soon updated to six, one of whom was suffering a suspected spinal injury, another with suspected head injury.

Among the patients treated at the scene were a 20-year-old man with a fracture to the clavicle, a 32-year-old who sustained significant facial injuries including missing teeth, a 58-year-old male who suffered a dislocated shoulder and a 35-year-old male suffering a decreasing level of consciousness.

Two other riders were also treated by paramedics at the scene, but their injuries were not reported.

A spokesperson for NSW Ambulance said three of the patients were transported via road ambulance to Orange Base Hospital, and another one was transported via road ambulance to Bathurst Base Hospital.

Another patient was airlifted from the scene by helicopter and taken to Westmead Hospital, while the final patient was taken via road ambulance straight to Bathurst Airport for transfer to Sydney via a fixed wing aircraft.

Despite Sunday's rain, the event continued under guidelines devised by Cycling NSW, Cycling Australia and The UCI.

Cr Hanger said the safety and well-being of competitors, officials, volunteers and event staff was foremost, saying conditions which might cause an event to be cancelled, suspended or modified include; extreme temperatures, fog, frost, hail and ice, flooding, snow, strong winds, thunder and lighting storms and torrential rain.