WA Police are at the scene of an armed hold-up at a pharmacy in the affluent riverside suburb of Applecross, south of Perth.

The incident on Thursday night is taking place at the intersection of Riseley Street and Canning Highway, with the highway closed in both directions.

It is understood there are no injuries, and all customers and staff have safely left the pharmacy.

However, the person who is armed is believed to still be in the building.

Officers used benches to barricade the front of the pharmacy, as the standoff – which began about 4.30pm WST – stretched into the evening.

Pharmacy 777, where the police activity is centred, posted on social media that it would remain closed until further notice “due to the incident unfolding”.

A large police presence is in the area. Photo: ABC News

“At this time, we can reassure you our team has been evacuated and our key concern is the safety of our local community,” the post read.

Helicopter vision from the scene shows tactical response officers with their guns drawn.

Ambulances are also on stand by, and there is a large police presence.

A nearby business owner, who did not want to be named, said there were “police and guns everywhere”.

He said no customers were able to enter or leave his shop on “one of the busiest nights of the year”.

Main Roads WA said emergency services were onsite and motorists in the area were asked to exercise extreme caution.

Canning Highway remains closed from Wilcock Street to Simpson Street in Applecross.

–ABC