Labour leader Jacinda Ardern says the Government need to be clear about whether it is involved in the Greenpeace spying allegations in any way.
"The idea that a group like Greenpeace is being followed by private investigators, essentially being spied on - in 2017 - is unacceptable," she said on Friday morning.
Greenpeace claims the Ministry of Business Innovation and Employment (MBIE) was involved in surveilling its staff and supporters.
The environmental group says private surveillance company Thompson & Clark Investigations was paid by oil companies Anadarko and Statoil to spy on Greenpeace staff members, and passed information to MBIE.
Ms Ardern, who is also Labour's security and intelligence spokeswoman, said "There needs to be transparency from the Government around the degree to which they've been involved.
"Were they given that information and then [was it] utilised in any particular way? It's not exactly clear their degree of involvement but I think members of the public deserve to know."
Greenpeace claims Thompson & Clark investigators followed its staff home at night, tracked their movements and took photos and videos of them in their private lives.
But MBIE insists the information it received from the investigators was limited to evidence for a prosecution against Greenpeace, and briefs of safety plans.
"We receive information about risks to on or offshore industry activities. For example, in relation to potential interference with an offshore activity, these may include pictures or locations of boats or trailers on ramps," a MBIE spokesperson told Newshub.
The evidence provided by Thompson & Clark included "photos, videos, etc. of the alleged incident at sea with the Amazon Warrior," the spokesperson said.
During that incident, which occurred in April, Greenpeace head Dr Russel Norman and two other activists jumped in front of the Amazon Warrior seismic survey vessel while it was working off the Wairarapa coast.
"Thompson & Clark were the security company on board the Amazon Warrior seismic survey vessel and have provided evidence... as part of the prosecution," MBIE said.
Dr Norman and two other activists were charged by MBIE with interfering with a seismic vessel, after a law change made it an offence to interfere with or get closer than 500 metres to a ship involved in oil exploration.
"Purely a matter for Greenpeace" - Bill English
Prime Minister Bill English on Thursday denied any knowledge of Government involvement in the alleged surveillance.
"I would be concerned if it looked like there was some surveillance of protesting, and we don't see any evidence of that. This seems to be purely a matter for Greenpeace and their private investigators," Mr English said.
"I just haven't seen any reason to believe that the Government would be any part of this current argument."
Dr Norman said Prime Minister Bill English should ensure no government agencies are involved in surveillance of activists.
"He clearly hasn't done that."
He said it's unlikely any ministers would know about the alleged spying, but said it's up to them to make sure their ministries aren't engaging with surveillance of activists.
"It's up to them to make sure that their departments aren't engaged in this kind of unethical and disgusting activity."
Dr Norman was a Green Party co-leader from 2006 until early 2015, and is a former member of Parliament's Intelligence and Security Committee, which has oversight of New Zealand's intelligence agencies.
Ms Ardern said, "I don't think it would sit well with anyone that Greenpeace in this day and age would be spied upon by private investigators, that's something that's part of our past and should [stay] part of our past."
Newshub.
