Shamrock Hut is 2 hours (4 km) up the Ahuriri Valley, at the end of Birchwood Road.
NZTopo50 map sheet: BZ14
Grid/NZTM2000 coordinates: E1330418, N5099540
Before you go, buy 1 Standard Hut Ticket (blue for adults, yellow for youth) for each night's stay. Put this in the honesty box at the hut. Or buy a Backcountry Hut Pass that gives unlimited use at most Standard and Serviced huts for a 6 or 12-month period.