NSW stabbing victim in serious condition

A man is in a serious condition in hospital following a stabbing in Sydney's southwest.

Police say they were called to an apartment in Cartwright at about 9pm on Thursday to find neighbours helping a 55-year-old man who had stab wounds under his left arm.

The man was taken to hospital, where he remains in a serious, but stable, condition.

Police are investigating whether the injured man was involved in an argument a short time before the incident occurred, though no one else was injured.