Work on an interconnector electricity transmission line between South Australia and NSW is to begin early, with the SA government putting up $14 million to get the project off the ground.

Announced last year as part of the new Liberal government’s energy policy, the connection was initially due for completion in 2021-22 but the latest funding could fast-track the projection.

“We are informed that if we do the early work we can shorten the time frame for this project by a year, maybe even longer,” Premier Steven Marshall told reporters on Saturday.

“We believe the $14 million will be recoverable once this project finally goes ahead.”

The interconnector will allow South Australia to import base-load power and export surplus renewable generation and is expected to cut $30 from annual household electricity bills.

Early works could include co-ordinated planning approvals across the country, community engagement and line route and selection works.

Mr Marshall has previously committed $200 million to the project, which will be undertaken by electricity transmission network provider ElectraNet.

But the state opposition says the money is being spent incorrectly and the contract should have been subject to tender.

“We’d like to know if someone else can build the transmission line cheaper, operate it cheaper than ElectraNet,” opposition energy spokesman Tom Koutsantonis said.

“We’ll never know that because the state government has already committed to giving this money to a private company, a foreign company.”

He said the $14 million early works package should have been funded by a private company instead of the government.

Mr Marshall announced the funding at the Liberal Party’s South Australian branch AGM, held in Adelaide on Saturday.

Energy was also a talking point for guest speaker Treasurer Scott Morrison, who spruiked the government’s National Energy Guarantee as a “sliding doors moment for energy policy in this country”.

He said he was confident the policy would successfully pass through the coalition partyroom, despite criticism from Liberals including Tony Abbott.

“Of course there’ll be discussions but it will have strong support because it’s the right plan,” he said.

“There is the opportunity to secure what is a consensus that has been built over the last year or more for the right way forward.

“That opportunity is now and I believe our government will seize it.”

-AAP