A second major energy retailer has unveiled big price hikes in gas and electricity from next month, just one week after AGL announced increases of up to $600 a year in some states.

Key points: EnergyAustralia announces hikes of close to 20 per cent

EnergyAustralia announces hikes of close to 20 per cent Origin Energy expected to follow suit

Origin Energy expected to follow suit Retailers blame closing of coal-fired generators and increasing gas demand, hail Finkel report as "solid blueprint" for the future

Retailers blame closing of coal-fired generators and increasing gas demand, hail Finkel report as "solid blueprint" for the future SA Treasurer criticises retailers for "profiteering"

EnergyAustralia has announced electricity price rises of close to 20 per cent for residential and business customers in both South Australia and New South Wales from July 1.

The combined electricity and gas bill of an average household in SA would increase by $470 a year in SA and $379 a year in NSW.

EnergyAustralia said electricity price hikes in Queensland would be contained to an average 7.3 per cent, due mainly to the Queensland Government's direction to the State Government-owned distribution network to keep prices low.

A third major east coast energy retailer, Origin Energy, is expected to follow suit in coming days.

Price changes for Victoria will be announced in December.

EnergyAustralia blamed the impact of higher wholesale power prices following the closure of large coal-fired generators, increased demand for gas by liquefied natural gas projects in Queensland, and reliability issues with some big generators.

"This is bad news for families and businesses and absolutely not what they wanted to hear," EnergyAustralia chief customer officer Kim Clarke said.

"In the past 12 months alone wholesale prices for both electricity and gas have surged, almost doubling in some states."

The company said it had recently committed an extra $10 million to expand its support for vulnerable customers and urged those with difficulty paying their bills to make contact.

EnergyAustralia price increases 2017–18

Market Electricity (average residential) Gas (average residential) Electricity (average small business) Gas (average small business) South Australia 19.9 per cent, $390 9.3 per cent, $80 19.9 per cent, $967 13.3 per cent, $936 New South Wales 19.6 per cent, $320 6.6 per cent, $49 19.9 per cent, $915 10.7 per cent, $1,043 Queensland 7.3 per cent, $130 11.3 per cent, $559

EnergyAustralia urges proper consideration of Finkel Report

EnergyAustralia said it was crucial that government and industry took time to consider the recommendations of the chief scientist Alan Finkel's report into the future security of the National Electricity Market.

EnergyAustralia owns a mix of coal, gas and renewable generation, including one of the nation's oldest coal power stations, Yallourn, in Victoria's Latrobe Valley.

"No-one pretends it's an easy fix but doing nothing means higher prices and less reliable energy for all customers," Ms Clarke said.

"We think the Finkel Panel's report is a good, solid blueprint for federal and state governments to work together on the bipartisan, national approach to energy we desperately need."

Retailers 'gouging' consumers: SA Treasurer

South Australia's Treasurer and Energy Minister Tom Koutsantonis lashed out at the major energy retailers and said they were gouging consumers.

SA Treasurer Tom Koutsantonis said the energy retailers were 'profiteering'. ( ABC News: Nick Harmsen )

"It's unacceptable. As far as I am concerned, they are profiteering. And they are leading the Government to believe there is not a competitive market in South Australia," he said.

Mr Koutsantonis made similar accusations after big power price rises last year. In June 2016, AGL announced a 12 per cent price rise, Origin Energy a 6.5 per cent increase and EnergyAustralia a 15 per cent increase.

He subsequently ordered an investigation by the state's energy watchdog, the Essential Services Commission of SA (ESCOSA).

ESCOSA's report, published last month, found the major retailers' price rises could "be justified by movements in the wholesale cost of electricity".

But it also suggested concentration of generation ownership could be limiting the effectives of retail electricity competition in SA.

Mr Koutsantonis said the Government would soon encourage a new competitor into the SA market with a tender to provide about 75 per cent of the Government's own electricity needs.

"When that new competition comes in I hope these companies get a lot of damage done to them," he said.

"Because quite frankly, I think the damage they're doing to South Australians is unfair. It's anti-competitive. And they can't justify it."