Police arrived at a Brown Road property in Labrador at about 4.30pm yesterday after being known as a couple of disturbance.
They started negotiations with a person who was within the residence alone and is believed to be unarmed.
An emergency lockdown was declared simply earlier than 7.30pm, with a unit block on the identical avenue evacuated.
Drivers have additionally been barred from the exclusion zone.
9News understands the person police are talking with has made threats to do hurt with a fuel bottle.
A number of police negotiators are on the scene.
"Some police officer got here and knocked on our door (and stated) 'it's a must to evacuate, there's something taking place'," one resident advised 9News.