The scene is set for a skirmish off the North Island's west coast this morning as protest vessels hold fast to Anadarko oil drilling ship the Noble Bob Douglas.
Anadarko had intended to begin drilling 185km off the coast of Raglan on Thursday or Friday but has been shadowed by a flotilla of six protest vessels.
One, the Vega, remains within the 500m exclusion zone.
Among those on board the 11.5m ketch are Greenpeace NZ chief executive Bunny McDiarmid and former Green Party co-leader Jeanette Fitzsimons.
Anadarko has said that the presence of the protest vessels would not prevent the drilling from going ahead but Greenpeace spokesman Steve Abel did not believe this.
"At the time they arrived [on Tuesday] they said they intended to commence drilling operations imminently but they haven't.
"Our understanding is that the presence of the Vega is stopping them from drilling and we don't believe they're going to drill while the Vega is there."
Mr Abel said neither police nor Maritime New Zealand had contacted Greenpeace about the Vega being within the exclusion zone.
Anadarko New Zealand corporate affairs manager Alan Seay said last week that the Bob Douglas was on track to begin drilling, despite the presence of the protest vessels.
Today Mr Seay told TVNZ's Breakfast the drilling was set to be under way by midday.
Protesters had stayed inside the safety zone and had yet to have an impact on the company's drilling operations but drilling would go ahead regardless.
"There's always a risk of something going wrong if somebody goes into a safety zone - it's like having an unauthorised person walking into a construction site," he said.
"We understand there are views right across the spectrum, there are people who are deeply opposed and there are times for those views, but there are also people who are very supportive of the potential economic uplift," he said.
More than 3000 people turned up at beaches from Muriwai to Wanganui at the weekend to oppose deep-sea oil drilling in New Zealand waters.