The cache is not at the posted coordinates; there is, however, parking here, albeit for a single car. Alternatively, park at the far end of Mopanui Road or at Orokonui Sanctuary and walk along the road to here.
Then follow the orange triangles to A22G - it's hard to miss it. To find the cache, take a bearing of 276.790 degrees from A22G and walk 15.667 metres - that's as the crow flies but you'll want to avoid the gorse, so take the easiest route - not that it'll be easy.
Don't forget to admire the view at A22G - all 360o of it.
CAUTION: the walk can be very slippery after rain or frost. Take care. Also, the turn into Mopanui Road can be tricky when driving; the road drops quite rapidly at the corner.