Environmentalists are worried about the effects on marine and bird life of a major dredging project planned for the Otago harbour.
The Port Otago Limited proposal includes dredging 7.6 million cubic metres of the harbour bottom.
The plan is to modify the shipping channel for future large container ship access.
The sediment would be dumped about 6.5km north east of Taiaroa Head.
Professor Liz Slooten from the University of Otago says environmentalists are worried about the likely effects on a nearby marine reserve, as some of the sediment is likely to end up there.
A public meeting about the project is to held in Dunedin on Monday night.