There were two De Havilland DHC-2 Beavers at Masterton. Above and below we have ZK-AZB (c/n 156) from Griffin Ag-Air Ltd, with its Fieldair scheme port side above, whilst below it is in the East Coast Air Services scheme on the Stbd side.
There are a swag of ZK-AZB pics on this blog. If you enter the letters AZB in the blank search slot near the top left hand corner of this page - they should appear.
Below we have ZK-BBX (c/n 324) the Jim Frogley, Havelock North based aircraft which is still actively involved in ag work. For more history type BBX in that search box. Or click on :-