Prime Minister John Key and Social Development Minister Paula Bennett are denying more and more New Zealanders the same opportunities to get ahead that they both benefited from, Green Party co-leader Metiria Turei says.

But in spite of pointed attacks on Mr Key in her speech at the Greens' conference this morning, Ms Turei said the party hoped to work with National on a plan to reduce electricity costs for struggling families.

Ms Turei harshly criticised National's record on environmental issues and social equality as she addressed about 200 party faithful in Christchurch.

However, Mr Key was the focus of her attacks.

"National have attempted to make John Key out to be a very nice, benign, fairly easy going guy," she told reporters later.

"In fact, he is the decision maker responsible for the failure to address inequality, for the failure to deal with key environmental issues like water and for the attacks on democracy that we've seen both in Canterbury and in Auckland."

In her speech Ms Turei said the Greens would continue to work towards reducing social inequality and child poverty, which the Government had failed to address in its Budget last month.

Later, she said former state house child Mr Key and Ms Bennett - who received state assistance as a young solo mother - had introduced policies that were making inequality worse.

"John Key is denying New Zealand's children the opportunities that he had as a child. Paula Bennett is denying women on their own with families the opportunities she had as a child.

"They've forgotten where they came from and forgotten who they are and where they belong in our community, and they are making the inequality worse."

Ms Turei said as a young mother herself, she had received a training incentive allowance to go to law school.

"I would not be able to do that now under Paul Bennett's changes."

Ms Turei is fronting the Greens' "Mind the Gap" campaign to address social inequality, which includes plans to deliver cheaper electricity to poorer families.

She said the Greens,who have co-operated with the Government on subsidised home insulation, would seek support from National for a version of what was once one of its own policies.

The "Hydro NZ proposal" for graduated power prices went through the select committee process under the National Government in the early nineties but was never taken further.

"This is not unknown to National as an idea. We would need to talk with them in a great deal of detail about how it would work. It's definitely something they could take up and it's not going to cost a lot of money."

Ms Turei's speech this morning "celebrated" her party's success in forcing the Government to change its agenda over plans to mine in the conservation estate, and promised to force it to back down further on the issue.

Mr Key's plan had initially been to mine "most of our national parks".

"But his agenda has changed because of us, the Green Party, and the thousands of New Zealanders who have joined with us."

She promised further action against the Government's "mining madness".

The Greens would look to attack the Government's mining plans further on the level of royalties paid to the Crown by mining companies and on petroleum exploration.

"We will make John Key's Government back down even further. We will prevail," she said.

Ms Turei said the success of the Greens' campaign around mining was reflected both in opinion polls specifically about the issue and also in wider political polls where National has slipped a little and the Greens have moved upward.

Green co-leader Russel Norman will speak at the conference tomorrow on how the party can better communicate its "No Environment, No Economy" policies around sustainable farming and industry and clean technology.

His speech will be followed by a debate and vote on a proposal to set out the Greens' candidate selection and party list ranking process in its constitution.

Internal dissent on the issue was made public this week when adverts were placed in several newspapers by a supporter of the proposal.