Shot fired by police in confrontation with knife-wielding man at Sydney park

Police have fired a shot in a busy Sydney park in a confrontation with a knife-wielding man. 

Officers were called to Marrickville Park, in the city's inner-west, about 3pm today.

In a statement, NSW Police said a shot was fired as police attempted to arrest the man. No one was injured. 

The man was arrested and taken to Newtown Police Station, before being transferred to the Royal Prince Alfred Hospital for assessment.

It is understood the park was packed with families at the time. 

"We were walking across the park and we saw a police van go through with lights on and then I heard a gunshot," one witness told 9News.

"I really didn't know what was happening so I looked for the nearest tree and then we just made our way out the park.

"My first thought when I saw the police car come though (was) 'hang on, there's lots of families here'.

"So it was pretty concerning when we heard the gunshot. Hopefully everybody's ok."

A crime scene has been established and a police investigation launched into the shooting.