Police are investigating after two officers opened fire on an armed robbery suspect in Sha Tin early this morning.

Just after midnight, a man with a knife robbed about $100 from a 21-year-old woman on Yuen Chau Kok Road.

The woman reported the incident to Police after the culprit fled on a bicycle towards Tai Chung Kiu Road.

A police vehicle discovered him riding a bicycle on Tak Yi Street. He was ordered to stop but refused.

Two officers got out of the car and attempted to stop him but he pushed one of the officers onto the ground.

The officer fired one shot after the suspect reportedly tried to attack him with a knife and ignored Police warnings.

In the wake of the suspect's non-stop attempt to attack the officer, the other officer also fired one shot.

The suspect, in his 40s, was shot on the left side of his neck and in his right armpit. He was sent to Prince of Wales Hospital for medical treatment.

The two officers felt unwell after the incident and were also sent to Prince of Wales Hospital.