The centrepiece of the former federal government's plan to secure Australia's future energy needs has been hit with significant construction delays, meaning it will not start producing electricity until late this decade.
The $5.1 billion Snowy Hydro 2.0, first announced by then-prime minister Malcolm Turnbull in 2017, is currently 19 months behind schedule.
That would push expected electricity production beyond the planned start of 2025.
Federal government sources have expressed surprise at the situation, and suggested information about the project from the previous government and Snowy Hydro itself was limited.
Energy Minister Chris Bowen is expected to seek briefings from the company in the near future.
Snowy Hydro has been contacted for comment.
Sources said the company could recoup some of those project blowouts, but even the best-case scenario still suggested delays to the project by around 13 months.
It is another headache for the nation's energy market, following a meeting of Commonwealth, state and territory this week to discuss the gas crisis gripping the east coast.
Soaring gas prices and a surge in demand, prompted by international markets turning to Australian gas in the shift away from Russian energy supplies, has hit the Australian market hard.
Adding to that, the cold snap across Australia has put more pressure on the local electricity market — hampered by unscheduled outages in Australia's ageing fleet of coal-fired power plants.
Former cabinet minister and now Nationals leader David Littleproud defended the delays on the project, which developed under the Coalition's watch.
"This is one of the biggest-scale projects we've done as a nation for probably a couple of generations, so of course when you do something as large as this, there's going to be delays," he said.
"And yes, we may not have got it all right, but it's something we're committed to and I'm sure that the new government will be committed to it as well.
"Let's be honest, this was always going to happen when you're building something as large as this, but let's just get on with it."
Prime Minister Anthony Albanese said it was not surprising, coming from the former government.
"We now know that there will be a blowout," he said.
"The former government — whether it be fiscal positions, whether it be delivery of projects — it was always about the announcement, never about the delivery."
Energy analyst Tony Wood from the Grattan Institute told ABC's AM the project was never the silver bullet to Australia's energy woes, but said the delay may have an impact on how the nation transitions to renewable energy sources.
"It's not going to cause the lights to go out by any means," Mr Wood said.
"But it's certainly going to mean there'll be a bit of rethinking about how we balance the wind and solar, and then there may be some adjustments to that.
"What I think is a little frustrating to say the least, is that the company had not been keeping everybody well informed about this, because 19 months is a pretty significant delay."