The increase, announced obliquely by a public notice today, was denounced by social welfare groups, who said it was “staggering” and “extraordinary”.

The utility said the average increase of $4.40 per week for a household using 5.02 megawatt hours per year was “mainly driven by the cost and availability of coal and gas supply for electricity generation as well as the changing mix of generation output”.

The price variation will take effect from July 1, and will appear on the first bill after that date.

SA Council of Social Service CEO Ross Womersley said: “This is just an extraordinary decision from AGL”.

“It does reflect the quandary that we have as a community, that every time we think prices are going down, we find they’re heading in the other direction,” he told FIVEaa.

He laid down to gauntlet to AGL’s competitors to lure customers with more attractive offers, saying: “If Origin are serious about wanting to grab a piece of that pie, today would be the very day for them to be announcing that they’re going to cut their prices, in the face of this announcement by AGL”.

Koutsantonis said around “one in two SA families are AGL customers”.

He said the price slug was “a dramatic increase… and quite frankly coal prices increasing interstate I don’t think justifies an increase in power prices”.

“I think what they’re saying really is there’s instability in the national electricity market,” he said.

“I think what AGL are doing is protecting their shareholders; my job is to protect SA consumers.”

Koutsantonis encouraged customers to shop around, urging them to “pick up the phone, ring around and change [providers]”.

“It’s a kick in the guts, it really is, and it shows how important it is that we start treating electricity the way we treat other commodities,” he said.

“Don’t accept this increase from AGL – start ringing around, try the other power companies… There are some much better deals.

“We understand there are bills out there that are nearly $800 cheaper per year than the AGL standing offer.”

He told FIVEaa it was “always possible” that the Government would consider extending an energy rebate, with his budget due to be handed down next month, delayed until after the federal election.

“Absolutely, we’d have to consider this,” he said.

AGL itself backed the Treasurer’s call to test the market, saying in a statement: “SA is a very competitive market and AGL has a range of competitive offers in the market. We are committed to keeping energy prices competitive and we encourage customers to shop around.”

Uniting Communities’ Mark Henley said AGL’s move “caught me off guard”.

“I’m pretty staggered by it,” he told FIVEaa.

“We’ve been pushing for a long time to get prices down.”

He acknowledged “there’s uncertainty in the marketplace about the future cost of generating electricity [and] that means we’re all going to be paying a premium for the uncertainty”.

Henley renewed his calls for a power price summit “that pulls all the players together”.

“We’re just sick of prices going up all the time,” he said.

Just yesterday, the Weatherill Government announced it would contribute $500,000 towards a million-dollar feasibility study to be conducted by ElectraNet to explore options for greater energy interconnection with the eastern states.

AGL this week announced it would increase average energy prices in New South Wales by $3.30 per week.