Suspended police officer arrested after attempted robbery

A suspended police officer is among three men arrested by heavily armed police after an attempted robbery of a woman in Sydney's south-west.

Some of the trio was dressed as tradies and wearing wigs.

The incident began shortly after 10.30am on John St, Cabramatta. Heavily armed police swooped on the scene, arriving before regular police.

A few bystanders were accidentally pepper-sprayed during the operation and were later doused with water by police.

A witness at the scene described hearing a woman “screaming”.

"One man... he was on the ground and another guy was holding on tight and wouldn't let him go and then another guy came over to get him off and then I came to help," he said.

The witness said that's when tactical police pounced on the men.

Another witness said he was upstairs working when police called to evacuate the building.

“I thought it was just our branch but it wasn’t, it was actually external,” he said.

“It was a bit scary… cops everywhere.”

A police spokesperson said the attack did not involve firearms.

One victim suffered a minor injury and was treated at the scene.

Police said the arrest was part of an ongoing operation between South West Metropolitan Region police and specialist units.