A new player has entered Sydney's controversial bike-sharing market despite the failure of two of its predecessors, Ofo and Reddy Go.

Lime launched on Friday with about 300 power-assisted bicycles and it plans to drop about 100 more on Sydney streets every night.

Green machines: Bright green Lime bicycles have appeared on Sydney streets, but scooters may soon follow. Credit:Lime

While the new bike weighs 35 kilograms - which Lime suggests makes it hard for one to find itself halfway up a tree - users can ride at speeds of up to 23.8km/h with the assistance of a Lithium battery pack.

The San Francisco based company - backed by tech heavyweights Uber and Google's parent company Alphabet - has plans for only about 2000 bikes, although it is most keen to introduce electric scooters, for which it is far better known overseas.