Police have launched an investigation following an alleged robbery and stabbing in Werrington this afternoon.
About 1.15pm, officers from St Marys Local Area Command attended Werrington Road at Werrington after reports of a robbery nearby.
Officers have been told a man, aged in his 30s, entered a newsagency at a shopping centre on Dunheved Road just after 1pm.
The man allegedly assaulted the male shopkeeper and took an amount of cash, before a further scuffle ensued between the pair.
The man in his 30s sustained stab wounds during the altercation and fled the shop.
He was stopped by police on Werrington Road, where he was treated by NSW Ambulance Paramedics, before being taken Westmead Hospital.
He remains under guard in hospital in a serious condition.
The shopkeeper is currently assisting police with their inquiries. He was not injured during the incident.
A crime scene has been established on Werrington Road, which will be examined by detectives and forensic specialists.
The roadway is also currently blocked while emergency services carry out their inquiries at the scene; drivers are therefore encouraged to avoid the area if possible.
Investigations into the matter are continuing and anyone with information is urged to contact Crime Stoppers.
Police are urging anyone with information about this incident to call Crime Stoppers on 1800 333 000.