Forty international boats were turned away from Whangarei's central marinas last year, with an $8.9 million marina on the cards to solve the waterway's parking problem.
Preliminary estimates put the benefit to Whangarei's economy at about $13.3 million annually for the proposed 100 new berths, adding to the $34 million already generated by the local marine industry, according to a preliminary feasibility study prepared for Whangarei Harbour Marina Trust.
The trust was responsible for the 181 Town Basin berths and 109 Kissing Point berths and is investigating setting up its third Hatea River site: 100 berths immediately downstream from Te Matau A Pohe on the west bank, just upstream from Limeburners Creek.
Trust chairman Brian Caulton said the two current central marinas had been operating at capacity for the past 10 years.
"It's all exciting. The industry in Whangarei is growing all the time with refit and shipyards, so we want to grow with that - we want to be ahead of the eight ball," Mr Caulton said.
He said each boat's occupants spent an average of $50,000 for every six months in the area.
"The problem we have at the moment is all the boats arrive about the same time."
The boats the trust turned away each season were usually referred to the 24-berth Riverside Drive marina, or Marsden Cove, which had 230 berths.
Whangarei district councillor Brian McLachlan, who represents WDC on the trust, stressed the project was still in the early planning stages.
The trust was putting together a concept plan for further consultation with iwi, before taking it back to council.
The feasibility study indicated the trust would need to borrow up to $8.1 million - potentially from the council - for the marina, which could include up to 60,000cu m of capital dredging, half of which would be used for land reclamation.
This would provide space for about 80 carparks, a marina office and common facilities.
Mr McLachlan said the trust was also considering competition from other Northland marinas. In 2015, Opua Marina was granted consent for an additional 173 berths.
"Part of the business case would be doing some market research," Mr McLachlan said.
"We need to go back and test those assumptions to make sure the market we feel is there, is there.
"Whangarei has a lot more to offer in terms of amenities, and an extensive array of businesses for people."
A likely option looked to be constructing the marina in two stages of 50 berths, allowing the trust to borrow less and test the market.
A change to New Zealand's temporary import entry rules in late 2014 also meant boats could stay in New Zealand for up to 24 months, as opposed to the previous six-month restriction.
Mr McLachlan said this, along with the fact Whangarei was promoting itself more in the international boating community, further increased demand for berths.
He said the district council was aware of the proposal and at this stage did not see any "fatal flaws" with it.
Mr Caulton said he was optimistic the marina could be operational within three years.