Putting parts of a controversial billion-dollar NSW power line project underground remains a possibility despite a potential major cost blowout.
The planned overhead HumeLink transmission line to Sydney from the state's south will be a crucial component in the National Electricity Market but has drawn criticism from farmers, local communities and environmental groups.
The 500-kilovolt connection involves running wires through bush and prime farmland, leading to calls for the project - initially slated to cost $3.3 billion - to be laid underground.
Speaking ahead of an inquiry hearing into the possibility on Wednesday, Energy Minister Penny Sharpe said various options were being examined to limit the impact of the project.
"It might be that there's a mix of things we can do - we need to work through it properly," she told radio station 2GB.
"I'm open to looking at whether (going underground) is possible and whether it doesn't impact in terms of cost and time."
Network operator Transgrid previously said going underground was unsustainable because of the time and expense involved.
Project chief Jeremy Roberts told an earlier inquiry hearing doing so could cost anywhere from $13 billion to $17 billion.
The projected cost of the overground project had meanwhile increased to $4.89 billion.
Ms Sharpe said she would wait to hear what the inquiry found before making a decision.
"It might be the case that there's a mixture of ways we can do transmission but I'm not going to go to the extent to say ... we can put it all underground," she said.
"I don't believe all of that is at all possible."
Wednesday's inquiry will examine the costs and benefits of similar projects and what impact a subterranean line would have on the environment and the project's timeline.
Links to other critical transmission projects, including connections to the state's five renewable energy zones, will also be examined.
Ms Sharpe said the government was committed to delivering a transition to renewable energy in a cost-effective and responsible way.
HumeLink will connect the Snowy Hydro 2.0 project to the NSW grid, including through Kosciuszko National Park.
Local MPs whose electorates will host HumeLink have called for more consultation, while proponents of running the lines underground have questioned the accuracy of the huge pricetag.
Wagga Wagga independent Joe McGirr said people were overwhelmingly running lines underground in Europe and California.
Snowy Valleys mayor Ian Chaffey said his community would be paying the price.
"You're asking this community to bear the brunt of this overhead monstrosity so people in metropolitan areas can have cheaper power bills," he told a hearing last week.
NSW is due to decommission three coal-fired power stations in the next decade, including Eraring, south of Newcastle, in 2025.
The loss of coal-fired stations from the national grid made it essential HumeLink was completed by 2026, network operator Transgrid has said.
