I am an agent in Brisbane, and standard practice in our office is that when there are two offers on a property, we have to get both buyers to sign a declaration saying they have put forward their best offer, and may not get another chance to do so.

So in your case, if you made an offer on a property, and then we received another offer, we would come back to you first and let you know that there is another offer, and you would have the opportunity to put forward your best offer.