The co-leader of the Green Party, Russel Norman, has asked for a halt on fracking in New Zealand until an investigation has been done into potentially harmful environmental effects.

Fracking is a mining technique that blasts apart rock veins to obtain hard-to-reach natural gases deep underground. It is currently being used in the Taranaki region.

Norman’s chief concern with the technique is about migration of chemicals from deep targets (1400m and deeper) to aquifers – layers of water-bearing rock or other materials from which groundwater can be extracted – at shallower depths.

Other effects the Green Party is concerned about include combustible water coming out of taps. Both this and contaminated groundwater have been documented in the US, most prominently in Josh Fox’s documentary Gasland.

According to a Stuff.co.nz article, TAG Oil – the Vancouver-based company conducting the fracking in Taranaki – completed its first fracture simulation to crack rock deep underground last year. Fracking was then used to break up rock deep in the Mt Messenger formation, boosting daily production rates by 365% by opening up paths through the rock. This involved TAG Oil using technology for the first time in New Zealand that it claims has been proven safe in the United States.

Norman says there has been no environmental regulation around fracking in the Taranaki region. “Taranaki Regional Council did not require consent, taking the view that there was no risk. Now they will require consent, but it is not clear if it will be notifiable,” says Norman.

In a recent blog post, Norman claims the council’s independent assessors decided fracking was safe and did not require a consent process. Now he wants fracking shelved until further evidence is gathered, with a view to nationally regulating the process.

However, Norman says regional councils are “reluctant regulators” driven by economics and benefit from the oil and gas industries working in the community and increased number of jobs. In order to effectively take a precautionary approach there needs to be national regulation on this type of mining, he says.

“These deep aquifers are valuabl. We do not want to damage them.”

Documentary maker Josh Fox told Radio New Zealand National last week that if gas companies say fracking is safe, they are lying.

“They are doing massive PR campaigns – the gas industry would like to position people making decisions like they are on a life boat in the middle of an ocean, saying you have to eat your sister. Well, that is not the position we are in. The smarter thing to be doing is to be developing renewable energy sources.

“These companies are pushing forward desperate measures, because natural gas is running out.”

Bernie Napp, senior policy analyst at Straterra, has publicly defended the practice in an online Herald article.

“All going well the only issue is that the water coming up needs to be disposed of in some way. We in the industry don’t have any problems,” Napp said in an interview on Radio New Zealand.

Asked about matters raised in the Gasland documentary, Napp said fracking was a complex area, and he was “not an expert on issues in the States”.

Julie Genter, a media advisor for the Green Party, says there are wider issues at play with fracking.

“The biggest problem with allowing fracking is that we take all the environmental risk, and it does nothing to transition us to a clean green economy. We have to get off fossil fuels – the sooner the better. Why risk earthquakes and groundwater contamination so that oil and gas companies can keep profiting off our dirty energy dependence?”

TAG Oil would not comment, saying only: “We feel there has been enough in the media already.”