Man stabbed in groin in Sydney's southwest

NSW Police are looking for a man who was last seen running down a street where another man was stabbed in Sydney's southwest.

Emergency services treated a 37-year-old man for stab wounds to his groin about 11.30am on Thursday before taking him to St George Hospital in a critical condition.

Detectives would like to speak with a man who was seen running north along Beamish Street in Campsie towards the train station.

He's described as being in his 40s with short, or balding hair, and about 180-centimetres tall.