There is no relief in sight from Australia's energy crisis with the nation's largest energy producer revealing several of its a coal-fired power units will be out of production for some time.

AGL Energy Limited on Friday confirmed its Loy Yang A unit 2 in Victoria's Latrobe Valley, which went offline in April, will not be fixed until "the second half of September".

The company blamed "global supply chain issues and the availability of specialised materials" for the outage extension.

The AGL statement said initially the unit broke down following an electrical fault in the generator, but now the generator rotor has failed extending the repair time by at least two months.

Almost one-quarter of Australia's coal-fired power capacity is offline, which includes about half of AGL's coal-fired units in Victoria and New South Wales, just as a cold snap hits the eastern seaboard.

Outages contributing to crisis 

At its Bayswater plant in New South Wale's Hunter Valley, AGL confirmed two units have been taken offline to fix issues, while another remains out due to scheduled extended maintenance and will be back online in July.

A company spokesman said Bayswater Unit 2  was taken out of service on Wednesday "to repair a tube leak and it is expected to be out for up to 10 days."

"Yesterday a maintenance issue on the Bayswater Unit 4 boiler ash conveyor required the unit to be taken out of service for a few days," the company said.

Consumers have been hit with higher electricity prices and gas shortages, with the new Labor government this week convening a meeting of state and federal energy ministers to discuss the issue.

This meeting resulted into a plan to safeguard the system and will also give the market operator more responsibility for supply.

And news on outages comes as the new Snowy Hydro development has been hit by construction delays meaning it will not produce any electricity until the end of the decade.

'Most unreliable power station'

Australian Institute climate and energy program director Richie Merzian said he was not surprised the Loy Yang A outage is being extended.

He described this power station as "the most unreliable power station in the entire grid" and said AGL should be doing more to phase out its coal electricity generation and move into renewables.

"That's been hurting people, especially in Victoria, which have been suffering a cold snap and everyone has been relying on their heat to keep warm."

Greenpeace spokesman Glenn Walker said Australia's transition to renewable's needs to be accelerated.

"The sooner we get clean, cheap, renewable energy into the system, backed up by batteries, the better it will be for the climate, the better it will be for Australian households."

Mr Merzian said it was encouraging the meeting of energy ministers this week also resolved to expedite the transition to net zero carbon emissions.

"They agreed they will come back in July and look at a plan at how to decarbonise the electricity sector," he said.

"So finally, for the first time, we will have that kind of thinking [to] make sure that the right people are in the room, and we support the communities along this journey."