Kiwis Against Seabed Mining say there is too much uncertainty around Trans-Tasman Resources' application for seabed mining off the west coast.
And their lawyer Duncan Curry used the words of the company's own expert to prove it.
Curry quoted the company's expert Dr Mark Hadfield who said "the uncertainty of the uncertainty is uncertain" when he gave evidence on the size of plumes in the Wellington leg of the Environmental Protection Authority hearing last month.
The authority hearing has sat in Hamilton this week to hear the submissions of about 80 Waikato people who are opposed to the application in the South Taranaki Bight.
The committee has thousands of other submissions against the application to take into consideration.
Curry urged the committee to dismiss the application on the grounds of uncertainty.
"The applicant should be sent back to properly carry out the scientific investigations such as baseline research and make a fresh application once that science is available," he said.
He also claimed the application breached the Treaty of Waitangi because it "fails to provide active protection of Maori interests and taonga, particularly over fisheries".
KASM chairman Phil McCabe said the west coast was a special place.
"Every stretch of this coastline is dearly loved and valued. I can tell you that the level of concern around the TTR and future proposals among coastal people is high.
"At no point prior to lodgement in October 2013 did TTR offer any evidence to support their claims around less than minor environmental effects. Pre-application consultation was done in an information vacuum. There was a consistent downplaying of effects and selective information sharing."
He called the company's claims that the site was generally not recognised as a habitat for marine mammals as "quite simply untrue". "TTR's supporting information is built upon an almost complete void of baseline environmental and ecological information . . . The EPA should have, in the first place, returned the application as incomplete."
The hearing finishes in Hamilton today and will reconvene in Wellington between April 14 and 16, then move to Taranaki and Whanganui between April 28 and May 2 before closing in Wellington around May 8.
The final decision will be released 20 days after the close of the hearing.