A man allegedly armed with a machete has died after being shot by police at a shopping centre in Sydney’s west.

NSW Police said officers were called to a car park at Westfield Mount Druitt at 3:15pm following reports of a brawl involving two groups of people.

They say while they were at the scene on North Parade, near Carlisle Avenue, officers were confronted by a male allegedly armed with a machete, who threatened them.

Police then fired a number of shots at the man.

Officers immediately rendered first aid to the man, who was then treated by NSW Ambulance paramedics.

Police said a critical incident was declared just after 4pm when the man, believed to be in his 20s, died at the scene.

A crime scene has been established and investigations are underway.

A woman said she was inside the Westfield at a children’s birthday party when she heard multiple gunshots.

“We were just in Timezone having a birthday for the kids, just an ordinary day, playing the games,” she said.

“And then next thing we know, a whole bunch of people just come running in, they were yelling that there’s a shooter running around.

“Next thing is we hear six shots go off.”