Legislation to sell New South Wales electricity generators has passed the Upper House of State Parliament, after a deal allowing hunting in some national parks.

The bill to privatise the state's power generators and sell or lease to Cobbora coal mine got through last night, 20 votes to 17, after the deal to garner the support of the Shooters and Fishers Party.

It will now return to the Lower House for final assent, because of amendments agreed to by the Coalition as part of the Shooters deal.

They include a four-year employment guarantee for workers.

The State Government expects the sale to reap $3 billion for Treasury.

Former treasurer Eric Roozendaal supports the sale but voted against it last night, telling Parliament the Coalition should have supported Labor's sale bid.

"I do think it's appropriate that we do sell the public owned generators, however Barry O'Farrell by his own stupidity has picked the wrong time," he said.

"Instead of supporting us when we brought the legislation to the house under [former premier] Morris Iemma, he has stumbled and bumbled to today.

"I wouldn't trust these bozos to do it in a month of Sundays."

Opposition Leader John Robertson was staunchly opposed to Labor's power sale plan, and says Premier Barry O'Farrell has broken a promise in a way that will put more pressure on household power bills.

"I always opposed the privatisation of electricity because it's an essential service. It's something that Government should own so they can make sure it is more affordable.

"We're now going to see energy prices go even higher. That means that even more families are going to have their electricity cut off.

"It's a sad day for the people of New South Wales... Our national parks have been turned into hunting reserves and Barry O'Farrell has broken one of his most significant promises and that was not to do deals with the cross-benchers."

The NSW Opposition and the Greens say the sell-off will inevitably lead to higher power prices. ( ABC News )

But Mr O'Farrell has defended the deal with the Shooters.

"Given it was clear that the Upper House that the electorate had given us, an Upper House that the Liberal-National parties do not have a majority in, was going to block the sale of generation, I had to do what politicians always have to do, balance public interest with the political realities delivered to me by the electorate," he said.

Treasurer Mike Baird says the Coalition's privatisation plan is different to Labor's, which he argued against in Opposition on the basis it would lead to higher power prices.

"The experts confirm that this is the way to put downward pressure on prices, for the Government to get out of there," Mr Baird told Parliament.

It is also good for employees and we are proud that we have put some protections in for employees into this bill, providing generous transfer payments, a two plus two year employment guarantee and importantly boosting the number of apprentices across regional New South Wales."

Greens MP John Kaye believes the money brought in now will be dwarfed by long-term losses.

"The only short-term gains will be for the New South Wales Coalition," Dr Kaye said.

"Every citizen of the state will be paying for last night's vote for now and into the future. This is going to be a long-term cost against households, against businesses, against our economy and against our environment."

A worker at one of the assets to be sold, the Liddell Power Station in the Hunter Valley, says the sell-off is an act of stupidity and greed.

"It's not a good result. We're going to see a lot of good, permanent, secure jobs put in jeopardy and we will get a pittance from the proceeds. It's a really terrible deal for the Upper Hunter, a good deal for Sydney," said engineering officer Graeme McNeill.

Hunting deal under fire

Under the deal with the Shooters, hunting of feral animals will be allowed in 79 and the state's nearly 800 national parks, nature reserves and conservation areas.

The sites opened up to shooters including Barrington Tops National Park, Mount Canobolas National Park near Orange and the Kosciusko National Park, except for the ski fields.

Critics have pointed to reassurances given by Mr O'Farrell in April last year.

"I have no intention of dealing deals with minor parties to sell out those plans, those principles, those programs," the Premier said at the time.

"There will not be a decision made to turn out national parks into hunting reserves."

Kevin Evans from the National Parks Association of New South Wales is angry at the deal.

"We are horrified by this announcement by the Premier. He's broken a pre-election promise to keep recreational shooting out of our national parks," he said.

"As announced, 34 national parks and 31 nature reserves will be now open to business for recreational hunters. Blood sports allowed in our protected areas in New South Wales as a result of this decision.

"I think the public are going to be rightly disgusted. This is just a real breach of trust."

There is also vocal support for allowing hunting though, from groups such as Field and Game Australia.

Deborah Kerr from the National Farmers Federation says it is welcome news for landholders.

"Ferals are a major major problem, you just have to talk to farmers who outline the issues they have around wild dogs, around pigs, around goats," she said.

"It is having a massive impact on farmers, so I am sure farmers would welcome the opportunity to have some impact on the growth of feral animals in public lands."