Household power prices could rise by more than 7 per cent from the middle of the year under the new WA Labor Government, with Energy Minister Ben Wyatt saying he could not rule out a hike of that size.

Key points: Power prices rises of more than 7 per cent could come into effect mid-2017

Power prices rises of more than 7 per cent could come into effect mid-2017 Energy Minister wants electricity prices to match cost

Energy Minister wants electricity prices to match cost New Government confident it can get legislation through Upper House

But Mr Wyatt denied he was laying the groundwork for substantial power price hikes by flagging a desire to eventually reach "cost reflectivity" — where electricity tariffs match the expense of providing the service.

Even if power prices rose by 7 per cent each year for the next three years, as is currently in the budget, that still would not be enough to reach cost reflectivity.

Asked if he could rule out power prices increasing by more than 7 per cent for the next financial year, Mr Wyatt said that was still a matter for Cabinet to consider.

"Clearly the energy system does need some reform and change going forward," Mr Wyatt said.

"But I am very aware that ultimately the cost falls to users. I'm not simply going to ratchet up costs without understanding what broad reform needs to take place.

"If you are not at [cost reflectivity] it costs the taxpayer a significant amount of money."

With consumer bills falling short of covering the cost of the service, the state currently subsidises electricity utilities by nearly $500 million.

Roe 8 termination cost debate

Another key decision that will impact the state of the new Labor Government's finances is the final cost of terminating the Roe 8 construction contract.

Labor had been confident that cancelling the contract would not cost more than $30 million, but the Liberal Party says its final advice before its election loss was the state would have to pay up to $145 million.

Transport Minister Rita Saffioti said her advice was the cost would be much less than the number floated by the deputy Liberal leader Liza Harvey.

Ms Saffioti says breaking the Roe 8 contract will cost less than the Liberals say. ( ABC News: Jacob Kagi )

"They [the Liberals] willingly put the state in this position so to have the deputy leader going around now about wasted costs shows they made a massive mistake when they signed the contract," Ms Saffioti said.

Meanwhile, the Government is confident it will be able to navigate a fractured Upper House after final results showed it would need to seek crossbench support to pass legislation.

Unless the Government can appoint a conservative MP to the role of president, Labor will need the support of the Greens and at least one crossbencher to pass legislation.

That appears to be the most likely scenario now, with the Liberals saying they will not allow one of their MPs to be president.

"I expect to have good working relationships with every member," the Government's Upper House leader Sue Ellery said.

The Upper House crossbench includes three One Nation MPs and one each from the Liberal Democrats and Shooters, Fishers and Farmers.