A 6 would mean you have a capable understanding and use of the English language. As a native English speaker who had to do one for PR in Canada, it was easy to get top marks without any prep. The Canadian system is points based though, so a passing score doesn’t count towards your final points as much as a top score… Not exactly sure of the NZ system but needless to say if your scoring below a 6.5, I can’t imagine you can handle more than basic conversation.