TREASURER Tom Koutsantonis has demanded the state’s biggest electricity retailers outline their reasons for the recent annual power price surge of more than $300, which will rank the state as having among the most expensive energy prices in the world.

Mr Koutsantonis revealed on Wednesday he had demanded explanations from AGL and Origin Energy over recent power decisions.

Mr Koutsantonis said he targeted the pair because they generate the electricity they sell. He said a check of the companies’ records found that established generation costs had not increased.

“AGL and Origin have costs of generating electricity which have not changed in the last year, but they are increasing retail prices,’’ he told The Advertiser.

“I have called them and spoken to them and I have said ‘how can you possibly justify these increases when your costs have not changed’.

“They are making super profits, with increased shareholder returns and no need or attempt to decrease their costs.

media_camera Treasurer Tom Koutsantonis arrives at the State Budget Lunch where BankSA withdrew its sponsorship at the Adelaide Convention Centre. Pic Simon Cross

“Poor people can’t accept $300 increases, they will turn the heaters off — all caused by privatisation.’’

The Treasurer ordered an inquiry by the Essential Services Commission of SA last year, after retailers announced double-digit price rises for households and businesses.

After similar increases at the start of this financial year Mr Koutsantonis again called on the independent Essential Services Commission of SA to investigate. It found the increases were justified.

Businesses and householders have been left reeling by planned price increases from the “big three” retailers, which control 70 per cent of the market.

The third of the big three in SA, Energy Australia, does not generate electricity.

“Gentailers” AGL and Origin generate 44 per cent and 15 per cent respectively of SA’s electricity.

The increases, from Saturday, have been used by utilities expert Bruce Mountain — a director of the firm Carbon and Energy Markets — to calculate SA will leapfrog notoriously energy-expensive Denmark to have the most expensive power prices in the world. Mr Koutsantonis questioned the accuracy of his figures.

One industry expert, who did not want to be named, said Mr Koutsantonis’ argument on prices was wrong because generation costs were only one aspect of the final bill increases.

A spokesman for Origin Energy said: “Prices are rising because of changes to the number and the type of power stations supplying the wholesale market that we buy from on behalf of our customers’’.

AGL made no comment.

Opposition energy spokesman Dan van Holst Pellekaan said he “ridiculed’’ the move as a “rehash of a failed stunt’’.