Man charged with assaulting NSW policeman

A man has been charged after he allegedly assaulted and then stole from a taxi driver before biting a police officer on the hand in Sydney's south.

The 40-year-old man punched the cab driver in the face and stole his wallet and keys during an argument over the driving fare in Riverwood on Thursday evening.

The driver followed the man to a nearby home and a further confrontation occurred.

Police separated the men and were searching the passenger for the keys when he bit one of the officers on the hand, police say.

Another officer's hand was injured when he intervened.

The passenger was charged with aggravated robbery and police assault and is due to appear at Burwood Local Court on Friday.

The two officers were treated for hand injuries at Canterbury Hospital.