NZDF has adopted a 7.62 designated marksman rifle for use at patrol level for observing and engaging target at ranges beyong the 5.56 steyr
New NZ Army Marksman Rifle - YouTube
Aus, the UK, germany and france have adopted similar rifles, also at squad level.
The US uses modified M14 rifles (M14 EBR). Aus, Fr, UK and US have all adopted the 7.62 version of the Minimi/C9 (the american one is called Mk 48 mod 0 and is slightly different. This is in response to longer engagement ranges in A'stan, and poor 5.56 stopping power and reach.
I think for the forseable future, NZDF and our allies will stick with the 5.56 as the standard individual rifle calibre. We wont change until everyone else changes. Given the cost of this, i don't think it will happen for a while. I have read (possibly on this website) that most of NZDF's 13 000 steyers are still in good order.
Australia is adopting an improved steyr, the EF88. I like the side opening grenade launcher, for longer 40mm grenades. Would be good to see nz have some of these.