I don't think we have an offical country music chart - just look up New Zealand Country Music and there are a few cool sites.
Here is the offical New Zealand top 40 chart link -
RIANZ
Cool thing is though I live in Hamilton (a city in the Waikato region) and in August the NZ Country Music awards are being held here!! My dad and I are going to go.
It's a great way for us te meet country artists and maybe pitch some of our songs (yes I have finally admited to the world I am a song writer!!)
In fact I will post another post with a link to a vid of my dads band so you can hear one of the songs he wrote.