A Taranaki farmer is involved in a tense stand-off with Shell after refusing to let the oil giant set off seismic surveying explosives on his land.

Photo: RNZ / Robin Martin

Nigel Douds initially gave permission but now says he wasn't properly informed of the potential environmental impacts of detonating the charges.

Mr Douds runs about 100 dairy cows on his Kapuni farm that has been in the family since the early 20th century.

He said when Shell Todd Oil Services (STOS) visited him ahead of the survey - which aims to build a picture of the mineral wealth underground - he was told the impact would be minimal.

"And one of my major questions was how many holes would I have on the property and they said maybe three on this side and possibly only one on the other.

"And I thought that's more minimal cause that's what they're talking about, but then to find there's 28 of them that's not minimal, not when they're in rows here and able to effect huge areas."

Mr Douds said the explosives were putting at risk his attempt to regain organic certification, and he wanted them removed.

"The situation is they just stay here until STOS can remove them and that's my position.

"I will never concede to letting them be exploded to minimise the risk because that is what we are trying to stop."

Photo: RNZ / Robin Martin

Taranaki Energy Watch spokesperson Sarah Roberts said Mr Douds' situation was just the tip of the iceberg.

"What we were seeing was real life situations which involved undetonated explosives where they hadn't gone off when they were supposed to and they were being left in the ground and also people were starting to talk about water quality issues with us.

"Now none of these risks were outlined to the families when they were asked to give access by the company."

Mrs Roberts said Energy Watch raised its concerns about the survey being a permitted activity with the Taranaki Regional Council in March.

"And now what we find is the regional council has retrospectively granted consent for up to 1300 properties without getting written approval which is required under the Resource Management Act.

"They must do it and they must get it from the landowners and as far as we are concerned this is unheard of."

The retrospective consent covers the 450 square kilometres of the Kapuni survey area and the 24,000 seismic shots - or 4.8 tonnes of explosives - on about 1300 properties.

In a statement the regional council's director of resource management Fred McLay said the issue raised by Energy Watch was technical in nature rather than a matter of environmental concern.

"The environmental effects of the discharges are less than minor so no parties are considered adversely affected and written approvals were not required."

Mr McLay said when the charges were set off the explosives vaporised and few contaminants remained.

"These are largely naturally occurring compounds, including nitrogen gas, water, carbon dioxide, carbon monoxide, aluminium oxide and calcium carbonate which are discharged in the bottom of the hole at depth.

"The conclusion is that the individual and cumulative effects are very minor and do not pose a risk to local groundwater supplies and users."

Photo: SHELL NZ

Shell Todd Oil Services general manager Rob Jager said he was aware regulatory matters had been raised about the survey and the company was working to resolve them.

Mr Jager said the company consulted with local councils before the project began and had acted in good faith.

"For our business, the safety of people and the environment comes first. Where shortcomings have been identified, we have sought to address them immediately in collaboration with the relevant agencies and individuals."

But Sarah Roberts did not think that was good enough and she wanted the Minister for the Environment to investigate.

"None of this activity has been consented with the landowners' knowledge which is appalling. We believe New Zealand Petroleum and Minerals, which issued the permits in the first place, should be involved and we should be informing the Minister for the Environment who these councils work under."

Mr Jager said STOS had been granted landowner permission to access 98 percent of the planned survey area and it would continue to work with these people to obtain important data to inform the future of New Zealand's oldest natural gas field.