Police have cordoned off a street in south east Perth after a couple made unknown threats on Monday.

Officers were called to the Douglas Road home in Martin about 9am on Monday to help another agency at the property.

A WA Police spokeswoman said when police arrived a couple in the home "made threats", which led police to cordon off the surrounding area as they attempted to speak to the occupants.

It is understood police are communicating with the couple through a fence at the property, and have ascertained they do not have a firearm.

It is not yet clear how many people are inside the home.