South Coast Board Riders Association counsel Brett Gray said the association believed the impact of the disposal of soil at sea or at three current disposal sites would have a serious impact on the city's protected surf breaks.
Its main area of concern was the application to dispose of soil at the Aramoana "spit" disposal mound and Heyward Point, which could adversely affect the quality of the wave produced there.
"This wave is recognised nationally and internationally as one of the best beach-breaks in the world. In good conditions, over 100 to 200 people can be surfing at that break."
Surfers had been aware of the adverse changes to the quality of waves directly affected by the disruption to the swell corridor since the port had been disposing of dredge spoil at Aramoana, he said.
The true effects of the additional disposal were unknown and although wave monitoring had been promised, it would not give an accurate picture of the effects.
The association and Surfbreak Protection Society spokeswoman Nicola Reeves said they did not oppose the dredging of the Otago harbour basin but hoped the port company would look at alternative ways to dispose of the spoil and called for independent analysis of the effects on the wave quality, installation of a camera above the existing dump site and robust monitoring of the spoil mound and effect on the Aramoana surf break four times a year.
Port Chalmers resident Naomi Wilson said Port Otago's expansion had caused significant impacts on port residents, including a phenomenal rise in traffic, modification to the landscape, loss of night sky, demolition of houses and incremental escalation of noise.
She was also concerned about the gaps in the environmental management plan on the effects of dumping.
Careys Bay resident Kris Nicolau said there were people in Port Chalmers still waiting for their homes to have noise mitigated.
"That doesn't bode well for us in Carey's Bay and other coastal communities who will be adversely affected."
She called for the panel to decline Port Otago's application to dredge 24 hours, seven days a week and dump spoil at sea and deny consent for the Boiler Pt extension.
If consent was granted, Boiler Pt should not be able to be used for night-time container activity.
