Depends on the context. In Australia it means "No problem" but unlike "no problem" in other countries it leaves open the possibility that it is a problem, but that they don't want the person to be worried. For example, "Yeah, it's a problem but we'll work through it. No worries." In contrast "No problem" literally means "it isn't a problem".
Source(s):
My Boss would say this privately to you about an issue to put your mind at ease just before he'd lambaste you for 5 minutes in a very public meeting over the same issue calling you names and using it to make an example to others of what happens if anybody screws up.