He intends calling to account Prime Minister John Key, Finance Minister Bill English, Energy Minister Gerry Brownlee and State Owned Assets Minister Simon Power, both in and outside Parliament.
Taking on such a formidable team in Parliament was no easy task, but Mr Parker was promoted last week by Labour leader Phil Goff because of the work he had done on policy and his ability to score hits on the Government through question time.
As a former energy minister, Mr Parker was well connected within the industry.
"I originally got active for Labour at the time the National government last had a chop at the electricity sector.
"Bill English was minister of finance and Max Bradford was minister of energy, and they forced Dunedin city to sell Waipori," he said in an interview.
The sale of the Waipori electricity assets made brokers a lot of money and left Dunedin poorer as electricity prices went up, he said.
Late last month, Prime Minister John Key announced Treasury had been asked for advice on the partial sale of four government-owned electricity generators: Mighty River Power, Meridian, Genesis and Solid Energy.
The Government could raise between $2.4 billion and $4.8 billion by selling between 25% and 50% of the assets.
Mr Parker said the assets were well run and returned money to the taxpayers who already owned the businesses.
"But the financial books of these companies are in such a bad position, the Government feels it can flog them off.
"It is symptomatic of the poor state of the economy that they think they can sell off assets New Zealanders have built up."
There was no true competition in the electricity market and it would be made worse if there was a partial sale of the assets, he said.
After the sale, directors would have a mandate to maximise profits and prices to consumers would go up.
One of the largest expenses households now faced was the monthly electricity bill.
Those bills would only get larger if the Government went through with the sale, Mr Parker said.
A report, commissioned by the previous Labour government and released in 2009 by the Commerce Commission, showed price gouging occurred within the electricity industry.
An extra 18% was being charged to consumers because of the lack of competition.
"Since then, the Government has done little to reduce them.
"Now, it wants to unleash a greater incentive to use that lack of market competition by partially privatising the companies."
Mr Parker said he was aware of the need for balance between electricity generation and the environment.
While that was a secondary issue, it was of great importance to Otago, which paid more than its proportionate cost of electricity.
Alexandra was close to both the Clyde and Roxburgh dams but residents paid higher electricity costs than major centres further away.
Asked what was so wrong with selling 25% of the energy companies, Mr Parker said New Zealanders already owned them, the sales would not be necessary if the Government had an economic plan and the sale would change the ethic of the companies towards profit maximisation.
Labour was determined not to let the electricity assets slip from the hands of New Zealanders, he said.
However, Dunedin Act New Zealand list MP Hilary Calvert said the planned asset sales did not go far enough.
She and other Act MPs would be campaigning for the Government to sell all assets it owned.
"Just because it is owned by the Government, doesn't make it the family silver.
"It's more like a tired plastic picnic set.
"The Government needs to stay out of business.
"It is not good at it and if the Government has billions tied up in direct business investments, it's not focusing on its fundamental role of providing infrastructure."
