I can confirm that this is definitely a stoat and it does have a black tip to the tail, look closely and you will see it.
This is the third stoat I've seen around my place, the other two our cat caught and killed. And before anybody jumps up and says a cat can't kill a stoat well I witnessed one of them along with two other people, was standing out the back and heard a commotion in a bush and out rolls the cat along with a stoat; after a brief commotion the cat had it by the neck and killed it.
Now our cat is no normal cat, we were given it from an ole boy down the lane that had a feral litter in his barn and didn’t want to destroy them, so ours was raised from a very young age by us and took a long time to domesticate her, she is very affectionate to us and our dogs but has caught many a large rabbit, rats and is great for killing moles, has even killed a large grass snake!!!