The government is seeking to alter its fast-track rules through an amendment Bill that would limit the time fast-track panels can spend considering decisions on projects to 90 days.
However, fast-track panel convener and former Environment Court judge Jane Borthwick said a timeframe of more than 90 days would likely be needed for a decision on the mine.
In a note to Australian mining company Santana Minerals, which is proposing the mine, Ms Borthwick said "based on the information before me, the scale, nature and complexity of the application suggest that a timeframe exceeding 90 working days may be warranted".
Ms Borthwick said she was consulting other people about the necessary timeframe before forming a "concluded view" but pointed to the "volume and complexity" of documentation filed by Santana.
There were 10 sought approvals, 22 proposed management plans and 10 sets of conditions.
The panel would likely require a timeframe of 110 to 120 working days, she said.
Understanding the hearing’s duration was important because prospective panel members needed to determine their availability, she said.
Subject to members’ availability, the likely date the panel could start would be February 2 next year, with a decision date of September 8 if the panel convened for 120 working days.
Ms Borthwick’s comments were welcomed by the Environmental Defence Society (EDS).
Chief operating officer Shay Schlaepfer said the fast-track panel needed "sufficient time" to assess the Santana proposal, which raised complex issues including ecological impacts.
The concept of a 90-day time constraint was "completely arbitrary", Ms Schlaepfer said.
The panel may need significant time partly because it has the power to invite and consider comments from anyone it considers appropriate, which includes organisations with relevant expertise such as EDS.
The amendment Bill had proposed restricting panels from hearing comments from anyone other than councils, iwi and adjoining landowners. However, the proposed restriction was scrapped from the Bill last week.
Santana had supported the restriction in a consultation response, saying fast-track rules had been "undermined" by panels inviting many people to comment.
The EDS, which has so far been invited to comment on two projects, Trans-Tasman Resources’ seabed mining proposal and Contact Energy’s Southland Wind Farm, applauded the news the "terrible" amendment had been scrapped.
Ms Schlaepfer said: "We’re particularly pleased to see that independent decision-making panels still have discretion to invite comment from appropriate parties."
Community group Sustainable Tarras, which has vociferously opposed the mine due to concerns about the environmental, landscape and economic impact, agreed it was vital appropriate time was taken to consider it.
Before lodging its fast-track application, Santana had not answered detailed questions about its proposal or released reports it had commissioned about it, the group has complained.
A spokesperson said: "From the outset, we’ve maintained that this controversial mine is not appropriate for fast-track approval."
The spokesperson added that a proposal to extend the North Island’s Waihi mine, heard under the fast-track process, had taken longer than 90 days and a complex, greenfield mine such as Santana’s proposal "would logically need far more time than that."
