Police arrived at a Brown Street property in Labrador at about 4.30pm yesterday after being called about a disturbance.
They began negotiations with a man who was in the residence alone and is believed to be unarmed.
An emergency lockdown was declared just before 7.30pm, with a unit block on the same street evacuated.
Some residents have remained behind and were told to stay indoors.я╗┐
Drivers have also been barred from the exclusion zone.я╗┐
9News understands the man police are speaking with has made threats to do harm with a gas bottle.
я╗┐Multiple police negotiators are at the scene.
Firefighters have also attended.я╗┐
“Some police officer came and knocked on our door (and said) ‘you have to evacuate, there is something happening’,” one resident told 9News.я╗┐
A neighbour said the siege had been “pretty quiet” through the night.я╗┐