A man has been charged with attempted murder after a police officer was stabbed in the leg with a sword in Sydney's south-west on Friday.

Police were called to a home on Werombi Road, Grasmere, about 5.20pm after reports of a concern for welfare.

Officers from Camden Police Area Command tried to arrest a 20-year-old man who allegedly threw a spear at officers before stabbing a 23-year-old probationary constable in the leg with a sword.

Police tasered the man before arresting him and taking him to Campbelltown police station.

The injured officer was treated by NSW Ambulance paramedics then taken to Liverpool Hospital in a serious but stable condition.

Police established a crime scene with officers seizing a knife, hatchet and spear for forensic examination.

The man was charged with 11

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