From all over, though in Canada, not NZ.

Developing agent:
Hydroquinone and phenidone or metol - mail order. One order can go a long way.
Ascorbic Acid - the heath food shop
Caffenol - coffee from the grocery store.

Alternatively - one bottle of Agfa rodinal or Kodak HC-110/ilfords Ilfotec HC commercial developers will when diluted as planned , go a long long way.

Preservative:
Sulfite - commercial food processor in the past - sausage maker. Now mail order.

Alkaline - Washing soda - sodium carbonate and borax- sodium borate - grocery store; Pool supply house is an option for the carbonate

Add Lye from hardware store - and with the CRC book as a reference , get to soduim metaborate (kodalk) from the borax, or buffered stop bath with soduim acetate from the vinegar

Restrainer - bromide - from mail order. Or Benzotriazole - much more concentrated - a stock solution of BZT , measured carefully can replace bromide

Stop bath - Vinegar for FB paper, or just water changed from time to time for film and RC paper.

Fixer - Hypo crystals - mail order, with a bit of sulfite and other little mial ordered bits. Or more frequently, 60% ammoinuim thiosulfate, by the gallon jug. Commercial Ilford fixer is just as good a deal, and works the same as most rapid fixers.

TF-4 from Photogrpahers formulary, or Superfix formula from APUG's Photo Engineer, will save hours of your life from otherwaise slow fixing processes.

Spend to buy a copy of Troop/Anschel 'the Darkroom Cookbook', and then build a spreadshet of the common elements that you will need.

I know Claire at JD Photochem outside of Montreal will mail ship all over the world. I get excellent service from her, as well as Mike at Artcraft, and the crew at the Formulary.