A new mobile phone company is challenging Telecom and Vodafone's hold on prepay customers.
Black & White is offering 30-day contracts - compared to the two and three year contracts offered by other providers.
The company is renting Vodafone's network on a wholesale basis, which allows it to re-package and price its own mobile services.
It will have no shops and will do business over the internet, targeting pre-pay customers.
Chief executive Jonathan Eele says customers who transfer to Black & White's mobile service can either keep their phone numbers, or swap to its 028 number range.
