The lawyer for Sustainable Otakiri has alleged the Environment Court made a number of critical errors when it considered a proposal by Creswell New Zealand Limited to take a billion litres of water a year from the Awaiti aquifer.

The community group is supporting an appeal by Ngāti Awa to overturn the Bay of Plenty Regional Council's decision to grant the company the consent.

Ngāti Awa's previous attempt to challenge the council's decision was dismissed by the Environment Court last year.

Sustainable Otakiri lawyer James Gardener Hopkins told the High Court the Environment Court should have considered the scale of the activity proposed by the company.

He noted Creswell wanted to take 5000 cubic metres of water a day, an amount he said was significant once compared to the 7300 cubic metres of water a day currently being taken by all other existing water bottling plants in New Zealand combined.

"I think that it is important to respond to my friend's suggestion that the Environment Court was entitled to take judicial notice that this activity was small in comparison to other water bottling activities occurring in New Zealand. My submission is, that is not the case.

"It is dangerous when the Environment Court has itself acknowledged that it did not have specific evidence on that for it to then make findings as to the comparative scale of this activity."

The Environment Court ruled that it was not within its jurisdiction to consider the impact of exports or plastic waste, particularly because bottles in itself did not require a resource consent.

Ngāti Awa has alleged the court, therefore, closed its mind to the impact the end-use would have at a local level.

Hopkins said it was impossible to separate the water-take from the bottling, and the court should have considered the impact of end-use.

"My submission is that the bottling is an essential part of the activity and that the Environment Court got it wrong when it said the primary activity was the water-take.

"We have an acknowledgement that the water would not be taken if it could not be bottled ... the water bottling is arguably the primary activity or, at the very least, an essential component of the activity, and it should not be considered as subordinate to the water take," he said.

Creswell New Zealand Limited - a subsidiary of Chinese Company Nongfu Spring - has proposed to produce 154,000 plastic bottles per hour over a period of 25 years.

That is 3.7 million bottles per day, 3 billion bottles a year and 33.75 billion bottles in total.

"That is what the Environment Court was asked to give consent for," Hopkins said.

"It rejected the ability to take into account the effects of those plastic bottles, 33.75 billion, into the environment. This is why this question of end-use and the effects of those plastic bottles in the environment has emerged through the course of the hearing as an issue and why, on appeal, my client says this is a critical issue that the Environment Court should have considered.

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"The scale requires it," he said.

Hopkins said another critical issue for his client was whether the company met the requirements of a rural processing activity.

"The applicant is trying to get into this definition by saying, 'the rural planned use activity is the water take, which means we're a primary productive use, which means we're therefore a rural processing activity, and therefore we're not industrial.

"My submission is they don't achieve that first step," he said.

Whakatāne District Council lawyer Andrew Green disputed that the company's proposal had not met the requirements for a rural processing activity.

"The majority [of the Environment Court] was correct to categorise the existing land use activity as a rural processing activity, going back to 1991. It was a consent to a water bottling plant. That's what Creswell has sought here," he said.

"It's still a water bottling plant, it's got some add-ons and it's expanded but that doesn't change its fundamental nature."

He said that was what the district plan envisaged, an operation that would process, assemble, and store products from a primary productive use.

"Through that processing, the water which is drawn from the ground stays in its natural state, no changes to it, no additives such as a twist of lemon, nothing else ... it's a natural primary product.

"In my submission, the proposal is consistent with the relevant, strategic and rural objectives and policies which are identified in the district plan ... and won't have an adverse effect on rural character."