Opposition groups are urging the Environmental Protection Agency to refuse to allow seabed mining off the South Taranaki coast due to a lack of solid information.
The application by Trans-Tasman Resources to extract ironsand from the sea off Patea has prompted a four-month hearing in front of an EPA committee. The application is winding to a close in Wellington and a decision is expected before the end of June.
Opposition groups Greenpeace and KASM (Kiwis Against Seabed Mining) said this week that TTR had failed to provide the necessary information on the impacts of seabed mining.
The EPA turned down a similar application three years ago because of a lack of information and opposing groups said nothing had changed.
"In 2014, the EPA gave clear directives as to the information that should be gathered before submitting a new application," the groups told the hearing.
"TTR did some new modelling on the sediment 'plume' and economics, but that was all."
Other key areas, such as marine mammals, benthic and seabird studies had not been undertaken, KASM and Greenpeace lawyer Ruby Haazen said.
"The South Taranaki Bight has not been the subject of any in-depth scientific or environmental research. TTR has attempted to convince us that there is in fact a lack of environmental activity in the area.
"The South Taranaki Bight is an environment that hosts an array of marine life, supporting some of the most threatened and rare species in the world and a feeding ground for seabirds, fish, marine mammals and a breeding ground for blue whales. This is only what we have found out so far."
Ms Haazen said TTR hadn't done any further marine mammal surveys for this second application, and even then those surveys were only between the mine site and the shoreline.
This contrasted with evidence given by blue whale expert Dr Leigh Torres, who confirmed many blue whales had been seen in the South Taranaki Bight, and it might be host to New Zealand's own population of blue whales.
Nobody really knew what the effect of noise from the mining would have on marine mammals, including the whales, she said.