Three female staff on the Smiths Chips Ferris Wheel at Sydney's Circular Quay have been left fearing for their lives after the door to the carriage broke off mid-air.

The three women were reportedly in a carriage near the top of the ferris wheel when the door got caught, ripped off and fell to the ground, causing the carriage and the women to lurch forward.

The incident occurred on the first day of the Smith's "Spin to Win" promotion near the Overseas Passenger Terminal at Sydney's Circular Quay.