A Newshub investigation has found a Chinese company drilled a 170m bore hole on a Christchurch site so it can bottle water for export.
The hole has been drilled despite a warning from the Christchurch City Council that it could interfere with the public water supply.
Officials have concerns the site may be contaminated, and that the new borehole may strike water used by Christchurch people.
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The former Kaputone wool scourer in Belfast, which used to clean wool, is now owned by Cloud Ocean water - and it has big plans.
Cloud Ocean Water owned an existing 33-metre-deep bore, but it has drilled a new 170m deep bore which is close to same place the Christchurch City council takes its water from.
Lawyer Peter Richardson, spokesperson for Aotearoa Water Action, says that is where the problems begin.
"We don't think it is right at all. We believe it is putting our drinking water supplies at risk, with no benefit whatsoever to the Christchurch community."
Christchurch City Council documents show the drilling has been done.
"Christchurch City Council Staff are aware the new well has been sunk and is being surged at present," one excerpt reads.
"Council Staff are concerned that any new take from the new depth may be from the same aquifer as our drinking water wells."
The council also warned of "well interference" in the documents.
"It's been shrouded in secrecy," says Mr Richardson.
Officials say the bore is on "land designated as potentially contaminated", which has got Councillor Vicki Buck worried.
"We've had to deepen all of our bores for our own water drinking safety, so we're taking from those bores," she said.
"What we don't want is anything that in any way interferes with that."
Newshub can also reveal that Cloud Ocean's ownership can be tracked back to Rizhao Lingyunhai Sugar Group Limited.
It is based in the south-east Chinese city of Rizhao, and is marketing water there.
The consent allows 1.6 billion litres a year. In China, the shelf price for 10 litres is $27, which means potential sales of $12 million a day or $4.3 billion a year.
Opposition to the bore is rising.
"The really important thing is the purity of our drinking water," Ms Buck said.
"So anybody taking from our drinking water, we have to be absolutely sure that they're not contaminating anything or interfering with it."
Legal action has now been filed.
"The process, we believe, is flawed - we believe it is unlawful," Mr Richardson said.