Originally Posted by
gowananddiane
I have found that Koru club works only on Air New Zealand tickets. So you can access a Star Alliance Lounge with Koru Club, if it is an Air New Zealand ticket. An example would be flying from Manchester to Auckland; if booked thru BMI lounge access would not be available; if booked through AirNZ then would get access at Manchester (probably) and LHR (certainly).
Gold status gives a lot more access to overseas lounges than Koru does.
New Zealand Koru has let me have access to the Auckland international lounge when flying star alliance to destinations that Air NZ does not fly to; I'm sure this courtesy is not extended to a 'one world' ticket.
Sometimes a lounge will let you in anyway, sometimes not.
Here are the rules, just as you thought.
5.6 Access to Air New Zealand International Lounges is subject to the following conditions:
(a) Members must present their Membership Card and Air New Zealand International boarding pass or ticket for same day departure on an Air New Zealand ticketed and operated international flight departing from that airport;
(b) Please note that in some airports, Members will be issued a lounge invitation at check-in for access to the lounge in that same airport;
(c) Access to an Air New Zealand International Lounge or associate airline's lounge is only available to the Member prior to the Member's boarding of an Air New Zealand International flight or at such other times as determined by Air New Zealand in its sole discretion;