UPDATED 11.47AM: Energy minister Simon Bridges has opened tenders for the 2015 Block Offer for oil and gas exploration.

He's made the announcement at the Petroleum Summit in Auckland this morning.

The block offer includes 425,000 square kilometres of offshore release areas in Reinga-Northland, Taranaki, Pegasus, and Great South-Canterbury Basins.

It also includes 5000 square kilometres at an onshore site in the Taranaki Basin and two in the West Coast Basin.

The Petroleum Exploration and Production Association say today's Government announcement on oil exploration is vital for the industry.

Chief executive Cameron Madgwick says at the moment Taranaki is our only producing basin.

"Look it's very important - in the long-term oil and gas are going to be a critical part of our energy mix," he says.

"It's important that we continue to search for more so that we can continue to produce more."

Green MP Gareth Hughes believes the the announcement goes against what the public wants.

"This is an economic strategy based on the Beverly Hillbillies, just hoping someone finds something down there and they don't leave too much of a mess."

Simon Bridges says oil is New Zealand's fourth largest export, and the $700 million it brings in each year in royalties and taxes help pay for roads and schools.

“The Block Offer regime provides an efficient and transparent process for oil and gas permitting, and has attracted investment from experienced and capable operators," he says.

“New Zealand has built a strong, world-class regulatory framework for economic opportunities, while ensuring environmental and safety protections."

The human toll of oil drilling and climate change was the focus of a silent protest outside today's event.

The speechless activists were a far cry from the loud rally at the same site yesterday afternoon.

But the group hoped the multi-canvas artworks they held up would tell a thousand words about the irreparable harm they say is caused by deep-sea oil drilling.

Police were guarding every entrance to the controversial event, to prevent any of the activists making it inside.

But delegates arriving at the conference still had a difficult time, with protesters flanking the main entrance, and onlookers and supporters spilling out on to the street.

Greenpeace campaigner Steve Abel says the announcement was made at a private event with strict security.

"They've got an increasingly siege mentality - it's very interesting, the extent of the security - it's unprecedented really," he says.

"That's a really bad sign for the industry."

Abel believes the future is in clean renewable energy.

"That's where the jobs and prosperity are in New Zealand and that's where we're asking these people in the oil industry to move.