Large telecommunications companies "have too much to lose" by matching Hawke's Bay-based NOW's level of service and "honest pricing" says NOW CEO Hamish White.
NOW has grown by at least 40 per cent for the past three years and next year's target is even more ambitious.
He said more than half of growth was in Wellington.
Its Lower Hutt office had 6 service and sales staff but the bulk of customer support is in its Napier offices.
NOW has 70 staff, with 30 hired in the past 12 months to cover growth in the mid and lower North Island.
It is growth funded by large incumbent competitor Spark, formerly known as Telecom, which bought a 26 per cent stake last year.
Spark was "very supportive" of NOW's strategy.
"They want us to be who we are. The minute we start looking like them, then they might as well invest in themselves."
He said the availability of fibre, with the Government rollout half complete, was causing market share displacement as people switched. Last month 80 per cent of new customers were for fibre - typically he said it was between 40 per cent and 60 per cent.
Incumbents typically lost customers so Spark's investment in NOW could be characterised as "if we can't beat them we may as well join them".
He said cracking the Wellington market was "a hard slog" but growth was self-sustaining thanks to word-of-mouth.
"Our business is predicated on exceptional customer service and our existing customers are our greatest advocates. The more customers you get the more growth you get."
He said NOW's call centre answered an industry-leading 95 per cent of calls within 60 seconds. Free home visits by a technician also helped satisfaction ratings.
"We are trying to own the position where we are the only telco in New Zealand where, if we can't fix your problem over the phone, we will come to your home."
A Consumer NZ survey of its 8600 members' 12 internet providers resulted in an 88 per cent satisfaction rate for NOW. Vodafone's rated 30 per cent and Spark 35 per cent. The average was 44 per cent across all providers.
The company plans to leave its Onekawa base for new offices but Mr White refuses to say where in Hawke's Bay it will be.
He was putting a lot of emphasis on a workplace environment "conducive to the environment that we are trying to build".
"Happy staff, happy customers."