Mr Nash said he had no problem with bottled water companies taking New Zealand water if it was sustainable.
"What I have an issue with is they are getting it for free," he said.
"The problem is, there is no legal way to actually charge for water."
Currently the Government is consulting on proposed freshwater reforms, and while there was an economic aspect to such reforms Environment Minister Nick Smith said the call from opposition parties for a moratorium or a new tax on consents for bottled water plants was "typically uninformed" and "scientifically unsound ... in respect of dealing with the challenges New Zealand has in freshwater management".
Mr Smith said New Zealand had 500 trillion litres of freshwater each year flowing through our lakes, rivers and aquifers, and we extracted only 2 per cent of that for human purposes.
"The total water extracted for bottled water is only 0.004 per cent of the resource."
He said it was wrong to target the bottled water industry in the broader debate about improving the system by which water is allocated and reducing the pollution of our rivers, lakes and aquifers.
However, regional councillor Rex Graham said there was a "disconnect" between saying water was free and giving it away for someone else to sell it, even if value was being added to it.
"You would think there is a community opportunity to get something back for the community out of all this," he said.
"But at the moment legally you can't, it is up to central government."
This is a notion that the Parliamentary Commissioner for the Environment, Dr Jan Wright, supports.
In her submission to the Government's proposed changes to freshwater policy she said it made economic sense to price water in catchments where it was scarce, or likely to become so, and where it was being used as an input to production.
"Water pricing is not a subject that I have investigated in any depth. But I do see merit in a system in which the revenue gathered would be spent on improving and protecting our rivers and lakes," she said.
"Sooner or later, New Zealanders must have a serious discussion about water pricing."
It is a conversation Mr Nash wants to have now.
"These [bottled water] privateers are drawing water directly from the ground, adding no value apart from a vessel and some packaging, and then selling it for profit," he said.
"This is wrong, utterly wrong, and it needs to change."
This week, council scientists revealed to regional councillors that the Heretaunga Plains aquifer had declined an estimated 2m from 1994 to 2014, and is estimated to be about 2m.
"The declines observed in groundwater levels probably reflect increased pumping over time," the report states.
Regional council's group manager of resource management, Iain Maxwell, said the declines seen across the plains could not be attributed to individual consents.
"It's the result of cumulative effects of all takes, whether it is water bottling or irrigation for crops or apples," he said.
However, Mr Graham said bottled water changed the state of play for the aquifer.
He said that aside from municipal takes, farmers would take water only for a certain time with the winter period giving the aquifer time to recover.
"Now we have added another component in there, which we don't really understand, and they say that they don't understand it.
"Well, why are we giving consents when we don't understand?"