The definition of a behavioural problem is roughly when the pain of having an animal outweighs the pleasure of having the animal. 

IF THE DOG IS SHOWING AGGRESSION TOWARDS YOU OR A MEMBER OF YOUR HOUSEHOLD ...

... you need to see a Vet Behaviourist.  Contact me for contacts within Australia or speak to your local Vet.

 

If a dog has suddenly changed personality or is getting progressively nastier and the behaviour is out of character, s/he may be in pain and should be checked first by either your Vet or the Vet Behaviourist.  Please advise them and their staff that your dog is/has become aggressive so that they can be prepared.  Thank you.  : )

You can also have telephone consults with a Vet Behaviourist (usually around 15 minutes - you will be charged and rates vary) - they will not want to see the dog "in action" as that just gives the dog another chance to practice the behaviour!  They can then advise you on a future course of action and/or whether you need to come in and see them.  (FYI, put some time aside as some initial consultations may take up to 3 hours.)

Don't take unnecessary risks and delay in asking for help - contact a Vet Behaviourist.