CentrePort has said its plan to dredge Wellington harbour will result in significantly less wave energy in parts, which has prompted surfers to speak out against the plan.

Wellington's surfing community has banded together to oppose CentrePort's plan to dredge part of Wellington Harbour, claiming it will destroy some of the most popular breaks.

CentrePort is proposing to deepen the harbour at two spots to allow ships with draughts of up to 14.5 metres through the harbour entrance and into the Thorndon container wharf.

Phil Wollerman, who has surfed in the Lower Hutt suburb of Eastbourne for the better part of 50 years, said the plan cut a seven-kilometre-long channel from the harbour mouth would "obliterate five of our best-loved local breaks".

SUPPLIED A map showing where CentrePort proposes to dredge the sea floor at the entrance to Wellington Harbour. Surfers say it would destroy five popular spots to the east of the deepening site.

The five spots at risk are known to local surfers as: The Rec, Lions Rock, Burdan's Gate, The Web and The Pipes, Wollerman said.

READ MORE:

* CentrePort reveals details of plans to dredge 7km channel in Wellington Harbour

* CentrePort plans $75m spend to expand services

* Port hopes to be deepening harbour within 12 months

"The angle and contour of the cut redirects swells across to the Seatoun and Karaka Bay beaches and roading."

CentrePort documents state the work will flatten waves at Eastbourne by a third and "lessen the amount of wave energy along the Eastbourne coast, which will result in a reduction in surfable days".

Its web page on the project says: "We have considered a wave-focusing device or artificial reef. However, our experts tell us that these will not be successful in that environment."

It says consultation is under way with surfers and the Eastbourne community to try to sustain "surfing opportunities" across the wider region.

Wollerman said he realised there was no other alternative to widening the harbour, but wanted to stop the dredging going ahead.

He has created a Facebook group, SOS Eastbourne, which attracted 100 members overnight, in an effort to urge people to make submissions to Greater Wellington Regional Council opposing the resource consent.

Other residents have spoken of concerns about the erosion effects at the southern Wellington coastal suburb of Seatoun and popular swimming spot Worser Bay.

Eastbourne surfer Felix Burton said: "I got my first barrel just down at The Rec, that will be gone. That's one of my greatest surf memories."

Another long-time resident, who gave his name only as Gordy, said: "You do this dredging, you take it away – it's not coming back.

"We all get in the water ... it's a big community thing."

CentrePort is understood to have filed for resource consent to dredge six million cubic metres of sediment from the harbour floor, which would be dumped into the sea off Fitzroy Bay, just outside the harbour's entrance.

A report by coastal engineer Richard Reinen-Hamill from Tonkin Taylor showed longshore drift of sand from the southern end of the beach to the north, Worser Bay resident Callum Strong said.

"While mitigation has been proposed for Seatoun Beach, where maximum wave heights could increase by 80 per cent, no mitigation has been proposed for Worser Bay."