An economic consultancy estimates Auckland's sewer collapse and resulting pollution has cost the city millions of dollars in lost recreational fishing.
The Hauraki Gulf Forum commissioned the New Zealand Institute of Economic Research (NZIER) to tally the cost of the major sewage overflows on people's access to the Waitematā Harbour for recreation and food gathering.
In September when the waste and stormwater pipe burst in Parnell, under a 13-metre-deep sinkhole, residents were advised not to fish in much of the inner harbour.
The NZIER report found the sinkhole cost between $5.2 million to $12.9m in lost fishing, and between $50.9m and $166.6m in total lost recreation and food gathering.
The average cost per day was between $1.02m and $3.33m.
"It is conservative in nature and limited in scope but demonstrates that such incidents have costs far beyond their immediate repair," the report said.
"This, in turn, provides further rationale for investment in resilient infrastructure to reduce the likelihood of further adverse effects and costs in future."
Earlier this year, the forum released a report showing the natural capital value of the Hauraki Gulf Marine Park, in economic and ecological terms.
The research, conducted by NZIER, showed the Gulf was worth about $100 billion to New Zealand, and provided a flow of value to New Zealanders in excess of $5b a year.
NZIER said the Parnell sinkhole was the first test case for the natural capital value model's ability to price specific events.
An above-ground bypass pipe now redirects wastewater in Parnell, but the remaining sewage still flows into the ocean when it rains.
The Hauraki Gulf Forum is a statutory governance board established under the Marine Park Act to advocate for the Gulf.