Marama Davidson has promised work to make sure the Government has options to stop mega-bottlers.

The Greens are pushing for a "water test" to be included on land sales to foreigners, meaning the Government would be able to stop people buying land for water bottling.

The party have won agreement from the Government to consider it as part of the second round of reviews of the Overseas Investment Act.

The move follows Green Party Land Information Minister Eugenie Sage's controversial decision to allow Chinese water bottler Nongfu to extract water from Otakiri Springs, near Whakatane.

SUPPLIED Green co-leaders Marama Davidson and James Shaw at the conference.

Sage complained at the time that she was essentially forced into the decision as the current law only allowed her to consider economic factors - not issues surrounding water usage.

That decision caused a lot of upset among the party's base and membership, with co-leader of the Young Greens Max Tweedie asking "what the f.... is the point of us being in Government?"

SUPPLIED Chinese bottling company Nongfu Spring applied through an NZ subsidiary, Creswell NZ Ltd, to draw 580 millions litres of water a year from Otakiri Springs, near Whakatane.

Co-leader Marama Davidson made the announcement at the Green Party conference on Saturday, her first since becoming co-leader and the party's first in Government.

The party had secured support from the wider Government to consider the changes as part of the wider review of overseas investment rules, but not necessarily support them.

"I'm stoked to announce today that the review of the Overseas Investment Act will now look at putting the protection of water at the heart of decision-making," Davidson said.

ANDY JACKSON/STUFF Land Information Minister Eugenie Sage faced a backlash from her own party over a decision to allow a water bottler to buy new land.

"Water is one of our most precious resources. Our lives and our environment depend on it.

"We need to ensure that we are not giving away this resource to international corporations to reap profits from at the expense of New Zealand's best interests.

"The 'benefits to New Zealand' criteria that can be used to approve or decline sales does not include water extraction – they should."

The second stage of the review follows the Government passing a change to rules last week which allowed a foreign buyers ban.

Currently water extraction issues can be considered by local councils under the Resource Management Act but not the Overseas Investment Office or ministers under the Overseas Investment Act.

Davidson said the decision Sage had inspired. If a water test was part of the act already she said Sage would have been able to decline the Otakiri Springs request.

"Community issues need to be taken into account when granting applications," Davidson said.

Davidson and co-leader James Shaw believed it would be a widely popular policy.

"People are really concerned in particular about bottled water and especially around the export of bottled water - the idea that you could have these large corporations paying virtually nothing for this resource," Shaw said.

SUPPLIED Co-leader James Shaw speaks to the Green Party conference earlier in the day.

A poll conducted by Newshub/Reid Research last year found 87 per cent of Kiwis supported a charge on bottled water exporters - including 91 per cent of Green voters.

Environment Minister David Parker confirmed those issues would be "carefully considered" during the review.

Water was a crucial part of Davidson's speech on Saturday afternoon, where she said the country "cannot go on the way we are".

"The Greens recognise the intrinsic value of fresh water and its inalienable right to be protected from pollution and overuse," Davidson said.

"But we are also very clear that Māori have rangatira and kaitiaki rights over water, guaranteed in Te Tiriti o Waitangi.

"Our rivers are clogged with excess nitrates, sediment and e-coli contamination. They are literally drying up due to over allocation. The fresh water standards for pollutants need to be drastically strengthened and rigorously enforced."

Davidson, who comes from the more left wing of the party, tied together social issues and environmental issues in the speech.

She said "degradation" of both the environment and social safety net was "the result of a system that pits us against each other and collectively against our earth, for the benefit of the few.

"Will we even have a habitable planet to live on? There is no time for complacency or half-measures. No time for tinkering around the edges of the status quo. We know that what is required is transformative and systemic change."