A panel deciding on the management of a Southland lagoon has questioned aspects of a proposal for future openings.

On Tuesday, a three-day hearing kicked off in Invercargill regarding the Waituna Lagoon — specifically, a joint application to periodically open it to the sea.

The lagoon forms part of an internationally significant wetland southeast of Invercargill but has been plagued by both high water levels and algae outbreaks.

Te Rūnanga o Awarua, DoC and Environment Southland hope to improve its fortunes by gaining permission to open it to the sea based on varying triggers.

But the proposal was met with some push-back from the panel, with Dr Ian Boothroyd concerned about the governance structure and how it would play out.

Boothroyd also questioned a lack of details surrounding the authority and role of each agency involved, while member Megan McKay said it was difficult to see who was ultimately responsible for the proposed activity.

Panel chair Mark St. Clair also had concerns, saying there was a lack of evidence on operational matters such as moving diggers.

He said there was no spill management plan, information on minimising disturbance, or refueling information, which was “standard” in a consent.

Protocol for activities such as disturbing shorebirds needed to be included in the consent, but the panel did not believe it was, subject to the joint witness statement.

DoC solicitor rōia Pene Williams represented the applicants and conceded there were some "level of detail" which wasn’t yet available.

In response to the chair’s concerns, she said she didn’t believe any of the joint witness statements addressed that issue.

Williams said they were committed to working with the community and other stakeholders to ensure the hauora of Waituna, which risked crossing a “tipping point”.

“It’s the bottom of the catchment, it’s the receiving environment. So it is at risk of nutrient build-up from excessive contaminant loads, and that can have an impact on its water quality.”

The lagoon supported taonga species and a diverse range of native fish, she said.

Dean Whaanga — speaking as a mātauranga expert — said the lagoon was a unique and vital part of Murihiku.

“It nourishes the health of our whanau and communities, the environment, economy and the quality of life.”

The proposed application helped achieve cultural aspirations and restore the mana and mauri of the lagoon, he said.

In 1976, the area became the first in New Zealand to be recognised under the Ramsar Convention as a wetland of international significance.

It was opened twice in 2024 under emergency powers after the previous resource consent expired in 2022.

LDR is local body journalism co-funded by RNZ and NZ On Air