More than 100,000 people a year view sperm whales with Whale Watch in Kaikoura.
Whale Watch's Australian operations could one day outstrip the company's South Island business, its bosses from both sides of the Tasman say.
Whale Watch, owned by Ngati Kuri, a Ngai Tahu hapu, is one of the country's best-known tourism brands, taking more than 100,000 passengers a year to view sperm
whales off the Kaikoura coast and turning over $10 million a year in the process.
The company entered the Australian market last year, investing $5 million on the Gold Coast in a joint venture with Sea World.
Whale Watch Australia chases blue whales - the largest animal known to have existed - in a season which runs from June to November.
Australian general manager David Robertson was in Kaikoura with Prime Minister John Key last week to celebrate the launch of the $2.5 million vessel Wawahia, the sixth in Kaikoura's fleet.
Mr Robertson said the industry was much smaller across the ditch with only 30,000 passengers a year.
After two seasons the firm, which has one 125-seat boat, had about 40 per cent of those numbers.
"We're about 12,000 passengers at the moment; that's enough to keep us going."
The company had future growth potential because during the season 22,000 whales moved between Antarctica and the Great Barrier Reef, coming close in to shore to give birth.
Many sightings happened within three nautical miles of land.
"What we have is a whale superhighway. It gives us a very good strike rate."
Expansion plans also included setting up shop in Victoria and developing technology to find whales at the very early and late parts of the season.
Kaikoura chief operating officer Kauahi Ngapora said opening the Australian operations was necessary as the New Zealand market was probably at capacity.
"This is our first foray overseas, and our goal is to be the best over there."
Many who had been with the organisation remembered its humble beginnings when kaumatua mortgaged their homes.
"In 1987, when we only got 3000 [passengers], everyone thought that was fantastic.
"We're really happy with where we're going."
Whale Watch Kaikoura is a finalist in Virgin Holidays Responsible Tourism Awards, and a delegation will head to London for the ceremony on November 11.
