The dredging of Tauranga Harbour is likely to start by the year's end.
Conservation Minister Nick Smith has given final approval to dredge but says he is disappointed the process has taken so long.
His resource consent sign-off, announced yesterday, will allow the port to widen and deepen its shipping channel, making the port accessible to much larger ships.
Port chief executive Mark Cairns said he was pleased and dredging would likely start by the year's end.
The first stage of dredging will cost $40 million to $50 million and be finished in between six months and a year, Mr Cairns said.
The second stage will allow the port to accommodate container ships carrying 8200 TEU's (twenty-foot equivalent units) and cruise ships of up to 347 metres in length.
"These preparations for more frequent ship visits and larger volumes of cargo will ensure we continue to meet the capacity demands of our customers and maintain our high productivity levels into the future."
The long wait to get final approval had been "challenging", Mr Cairns said.
Dr Smith said New Zealand exporters and importers stood to gain efficiencies of more than $300 million a year as a result of larger ships being able to dock.
The structure of the old Resource Management Act had allowed the resource consent decision to drag on a lot longer than it should have, Dr Smith said. "I am disappointed that it has taken nearly four years for a final decision to be made on these consents. This is one of the last being dealt with under the old RMA.
"The Government's 2009 reforms would mean future consents of this type would be determined by the Environmental Protection Authority, rather than the minister, and within nine months."
Three Maori groups challenged the port's resource consent, granted in 2010, in the Environment Court in 2011.
When the Environment Court also approved the consent, Ngati Ruahine hapu took the matter to the High Court, saying the court had not properly considered how the consent conditions would provide for the relationship between the hapu, the harbour and Mauao.
In September last year, the High Court dismissed Ngati Ruahine's appeal but the hapu indicated it would appeal to the Court of Appeal.
However, the High Court judge did not give the hapu leave to make an appeal and the legal saga came to an end yesterday with Dr Smith granting the consent.
"The consent application to dredge the harbour to accommodate larger ships has been a challenging process for both iwi and the port over the last four years and the port has learned a lot throughout the process, of the Mauri that Tauranga Moana place on Te Awanui [Tauranga Harbour] including Mauao," Mr Cairns said.
Ngati Ruahine spokesperson Lance Waaka refused to comment when contacted by the Bay of Plenty Times yesterday.