While Statoil stated its decision was based on a low probability of economic returns from drilling in the Reinga Basin, Greenpeace and other opposition groups believed they had an impact on the decision, Mr Smith said.
"There are probably a lot of other factors, including the collapse of the international oil price and a worldwide move away from using fossil fuels, but there has been such widespread opposition, it has to have had an impact.
"It's possible they're (Statoil) also embarrassed about the timing of the Sami parliamentary visit."
Ms Keskitalo and the Sami delegation will meet with iwi leaders and other groups across New Zealand: "But in terms of Northland, it's a celebration," Mr Smith said.
Statoil's New Zealand operation manager Brynjulv Klove said that while "some may speculate" about why the company has surrendered its permits, "the only reason is that we see the probability (of a large discovery) too low to justify continuing our search."
Mr Klove said Statoil had worked hard to establish positive relationships with iwi, community leaders, local politicians and businesses.
"We are very grateful to the people of Northland for their support and hospitality.
"Our focus will now shift to four exploration permits of the south East Coast of the North Island and to exploration projects elsewhere in the world."
Mr Smith said Northland Greenpeace, hapu and other iwi groups would now support East Coast iwi in their fight to stop offshore exploration.
Earlier this year Energy and Resources Minister Simon Bridges said oil was a significant export earner in New Zealand and natural gas was vital to industry, electricity generation and households.
Greenpeace has accused the Government was "propping up a sunset industry".
Statoil is in the top 10 oil producers in the world and has operations in more than 30 nations.
