Residents, fishermen and environmentalists have opposed a proposed expansion of Port Otago at a resource consents hearing in Dunedin.
More than 100 submissions were made against the proposal, which would see the channel deepened to make way for larger vessels.
Consents are being sought for the multimillion-dollar Next Generation project which would see the channel dredged to a maximum depth of 15 metres over the next 20 years.
The Otago Regoinal Council believes port expansion would provide an economic opportunity for the region. Most objections relate to commercial activities, the environmental impact and fishing.
The regional council owns the port, so an independent panel of three people - two appointed by the council and one by the Ministry of Conservation - is conducting the hearing.
Opponents far outnumbered those speaking in favour at the hearing on Monday.
Many are worried about where the 7.2 million cubic metres of dredged material will be dumped and what it will mean for the surrounding habitat.
The Royal Forest and Bird Protection Society says there is not enough information about how marine organisms, birds and mammals are likely to be affected in Dunedin.
Local bird-watcher and ornithologist Derek Onley says 20 species viewed at the site are already considered endangered or at risk because of declining populations.
The independent panel will hear more submissions this week, with the applicant's right of reply still to come.