The Government is exploring legal options that may see it dispatch a navy vessel to stop Greenpeace from interfering with Petrobras' search for oil and gas.

But although Petrobras executives were reportedly reduced to tears after meeting with East Coast locals opposed to their work, Mr Key says the Government has not been asked by the giant Brazilian company to intervene.

Recent days have seen swimmers from a protest flotilla of five vessels forcing Petrobras' seismic survey vessel Orient Explorer off course in the Raukumara Basin, off the East Cape, and disrupting its work.

Mr Key yesterday said his Government respected people's right to protest, "but we also respect the rights of other people to carry out legal activities like Petrobras is".

The police and their minister Judith Collins were exploring "all of their options" with regards to the protest and Mr Key said sending a naval patrol vessel "could be" one of those options.

However, given the area in which the exploration lies in New Zealand's exclusive economic zone - which lies from 12 to 200 nautical miles offshore - it was unclear what the police and Government's powers were.

Ms Collins had asked officials from Crown Law to clarify that.

Mr Key said the Government had done that "off its own bat" and a spokesman for Acting Energy and Resources Minister Hekia Parata confirmed Petrobras had not asked the Government to look into the issue.

Meanwhile, an airforce Orion aircraft had also been dispatched to the area on an "observation" basis.

Police Superintendent Barry Taylor told National Radio the aircraft had been dispatched at the request of the police, but he was not aware that police had received a complaint from Petrobras about the protests.

Police powers outside the 12-mile territorial limit were the same as under New Zealand law, he said, though police were also exploring legal options.

The Green Party yesterday said it wanted an end to deepwater exploration in New Zealand waters, including Petrobras' current seismic survey, until there were assurances that a blowout and oil spill similar to the Deepwater Horizon catastrophe in the Gulf of Mexico last year could be swiftly dealt with.

Labour's energy and resources spokesman, Charles Chauvel, said his party opposed granting licences for deepwater exploration in the absence of environmental protections.

Mr Key said the Government was conscious of environmental issues and "we are in the process of introducing legislation that will address environmental concerns for deep sea wells".

"It is the Government's view that we can balance those environmental concerns with the desire of a great many New Zealanders to create better jobs and better incomes."

Greenpeace climate campaigner Simon Boxer said given there was no environmental protection framework for the area to be explored at the time the Government granted Petrobras the licence, his organisation did not believe the exploration work itself was legal.

"We believe the permit process is flawed from the very beginning and the Government has not done due process on this," he said. "If they want to take us to court we're more than happy to attend and be prosecuted. We believe they won't do that because it will actually be an opportunity to put all these international and national issues before a judge and they would run the risk of losing that court case."

Meanwhile, Ani Pahuru-Huriwai, of protest group Ahi Kaa, told the Herald she had helped organise a meeting on Sunday between Petrobras executives and representatives from protest groups and iwi Te Whanau a Apanui and Ngati Porou.

The executives were not accorded the powhiri and other honours at Te Araroa's Hine Rupe Marae which visitors might otherwise expect.

Ms Pahuru-Huriwai confirmed two of the Petrobras executives began crying during the meeting when faced with the strong opposition. She said the executives talked about their workplan, their commitment to environmental protection and financial capacity.

"We weren't interested because it's not about money, it's mana and our ability to feed our families from our traditional 'supermarket'."

* Petrobras is searching for oil and gas in New Zealand's exclusive economic zone - from 12 to 200 nautical miles offshore.

* Protesters are blocking the work.

* Government has asked Crown Law to clarify legal options in that zone, including whether the Navy could be called in.

* Police say their powers outside the 12-mile territorial limit are the same as under New Zealand law - but are also exploring legal options.

* Protesters say the search is illegal.