The Liberal leader today insisted the Opposition’s “Infrastructure SA” policy – which it took to the 2014 election – remained on the table. It commits a Liberal Government to establishing an independent statutory authority to oversee all state infrastructure spending.

But Marshall told InDaily he believed the establishment of such a panel would take time – whereas he wanted the masterplan for his policy blueprint unveiled on the weekend fast-tracked within 100 days of forming government in 2018.

The Weatherill Government has dismissed the freight infrastructure plan as a multi-billion-dollar attempt to sandbag Liberal-held Hills seats from the threat of a Nick Xenophon Team takeover at the state election.

But Marshall said the problems of disruptive freight corridors through the hills were long-standing and insisted: “This is a project we’ve been working on since 2013.”

However, he appeared to suggest the plan did not hinge on the marquee aspect – a new airport at Monarto – explaining it was a multi-pronged policy featuring a new northern bypass rail freight corridor, a corresponding road freight carriageway and the “possibility of a 24/7 freight-only airport”.

Asked if that meant the plan could proceed without the latter component, Marshall said: “That’s what we need the masterplan for, but people are telling me fresh food and accessing markets in Asia will become a big industry”.

“We have every confidence we’ll proceed,” he said.

The Liberals’ policy has received mixed reviews since its unveiling in the media yesterday, with former Major Projects supremo Rod Hook today notably endorsing further investigation on its merits.

“I like bold vision by any political party, whether it’s Opposition heading into an election or Government,” Hook told Leon Byner on FIVEaa.

“Is this worth looking at? My answer is definitely yes.”

Asked if the plan stacked up, he replied: “We don’t know yet and I think that’s why you would do the investigation.

“We would know without looking at it there are some obvious wins… it does take trucks off the freeway and I think that’s still an issue.”

The SA Freight Council has been the most vocal critic, arguing yesterday that a new air hub could undermine investment efforts by the existing airport.

Adelaide Airport Limited told InDaily it had no comment to make at this stage.

But Civil Contractors Federation chief Phil Sutherland argued “the Liberals have been criticised for years for not having policies and plans [and yet] they’re still being criticised”.

“This is what the people at the next election will be looking for – a competition of ideas put forward by the political parties,” he told FIVEaa.

“As for this proposal, the feasibility study the Liberals are proposing is the proper course.”

But it also appears to be just the sort of proposal Marshall was referring to when he first introduced his Infrastructure SA concept, designed to “maximise our infrastructure build by providing stronger governance, increased coordination and greater accountability”.

“Having an independent statutory body oversee infrastructure spending is proven to work,” the party’s 2014 policy document stated, arguing the oversight would “open up the decision making process by allowing full public scrutiny of infrastructure plans [to] increase transparency and public confidence”.

Marshall said today: “We’ll certainly be setting up Infrastructure SA, but this [Globe Link] is something we’ll want to fast-track the masterplan for.

“To set up Infrastructure SA requires an act of the SA Parliament, and that’s going to take some time to get through.”

But he insisted that it would “ultimately be a project that Infrastructure SA have an involvement with”.

“They’re in parallel just because of timing; if we had been elected at the last election, Infrastructure SA would be doing this work [now, but] to set up a new statutory authority takes time…

“We feel so strongly about the Globe Link project, we want to fast-track the masterplan for this.”

He said he had committed to a “fully-funded masterplan within the first 100 days of a Marshall Government”.

“I’ve been overwhelmed with the support for this project,” Marshall said, insisting it demonstrates “a vision that the people of SA need”.

With a likely pricetag into the billions – with $20 million already committed to developing a business case – Marshall agreed the policy unveiling suggested a shift from the Liberals’ previous small-target strategy.

“Look, we’ve always said 2017 will be the time when we switch gear and present our positive policies to the people of SA,” he said.

He added that he was “very proud” of the policy platform the party had announced in the previous three years, but conceded “some change is required in the lead-up to the next election”.

“The real issue is now making sure we get a majority Liberal Government at the next election, and we need positive policies to convince the people of SA that that is the solution to the problems Labor’s caused,” he said.