Newly released documents show Economic Development Minister Steven Joyce made a "backroom deal'' with oil company Shell over the ban on protesting in the exclusive economic zone, the Labour Party says.
The law change last month banned protesters from demonstrating within 500 metres of ships or oil platforms within New Zealand's 500km exclusive economic zone.
Penalties include fines of up to $100,000 and a year in prison.
Documents released to Labour under the Official Information Act show Mr Joyce had back-to-back meetings last September with Shell New Zealand chairman Rob Jager, business advisor Chris Kilby and chief executive of the Petroleum Exploration and Production Association David Robinson.
Labour energy and resources spokeswoman Moana Mackey said the papers showed the ban on protesting at sea was forged in a meeting with Shell.
"Shell provided a paper to Mr Joyce expressing concern that there was 'insufficient legal authority' to clamp down on offshore protests and that the Government 'has no teeth beyond 12 nautical miles to protect legitimate commercial activity'. Within a month work began on the changes.''
Ms Mackey said the papers showed Energy and Resources Minister Simon Bridges met with Shell again on February 14, just two weeks before he took a paper on the protest changes to Cabinet.
The paper quoted advice from Ministry of Business, Innovation and Employment officials that the oil and gas industry had sought "a more robust Government response to threats of, and actual, direct protest action''.
It also noted there had been no public consultation - which Ms Mackey said typified the Government's approach.