Commenting this morning on what Labor described as a “stunning leak” two weeks out from the State Budget, the Premier said there was “still some work” to be done on the new school and “we’ll announce that as soon as we possibly can”.

Treasurer Rob Lucas said it was “just one of many requests for funding” and a “final decision” would be revealed in the budget.

The “sensitive” document – titled 2021-22 Budget, Cabinet Committee Critical Priority – shows a proposal from Gardner to spend more than $80 million on a new Year 7 to 12 school at Norwood Morialta High School’s Rostrevor campus.

Opposition education spokesman Blair Boyer says insiders have told him the school would open in 2023 and cater for 1200 students.

In its first year, it would take in Year 7 students, with other year levels starting in 2024.

The document, seen by InDaily, includes a heading “Future Use of Norwood Morialta High School Rostrevor Campus – proposed establishment of a new 7-12 High School”.

It states: “Due to the current pressures and constrained sites of many eastern Adelaide high schools, Norwood Morialta High School’s middle school campus at Rostrevor is proposed to be used by the department.

“Based on demographic analysis, it is proposed that a new 7 to 12 high school be commissioned to meet growing demand for government secondary schooling in this area.”

Under the title “Minister’s Proposal”, it shows nearly $37 million would be allocated for the school next financial year, more than $42 million in 2022-23 and another $2.5 million in 2023-24, totalling $81.7 million.

Boyer said the leak had “revealed one of the Marshall Liberal Government’s centrepiece announcements for the upcoming State Budget”.

“It is remarkable such a significant announcement in the government’s budget has been blatantly leaked to the Opposition in a bid to undermine the Premier and John Gardner,” he said.

Boyer also questioned why a new school was being planned for Gardner’s Morialta electorate in the eastern suburbs when education officials had previously cited the need for a new school in the Prospect area, following capacity concerns at both the Adelaide High and Adelaide Botanic shared zone and Roma Mitchell in Gepps Cross.

“Labor supports investment in schools, but it would be interesting to see Education Minister John Gardner’s justification for building a new school in his own electorate, when his own department’s boss has highlighted the need for a new school in the inner northern suburbs,” he said.

“Have investigations been undertaken into the competing needs of both areas?”

Premier Steven Marshall said the new school had already been flagged by Infrastructure SA in March.

“There’s still some work to be done on the new high school out in the east to deal with some of the population challenges that we have and we’ll announce that as soon as we possibly can,” he said.

“We want to constantly upgrade our school facilities right across South Australia.

“We already have four brand new schools in our state and upgrades to about 100 of our schools in South Australia to facilitate that transfer of Year 7 from primary school into secondary school.”

When asked why a school was being planned for Rostrevor and not the Adelaide/Prospect region, Marshall said “the department provided us with advice that the most urgent need was actually in the east”.

“We know that our schools in the eastern suburbs have been massively over capacity for an extended period of time,” he said.

“Whether that be Glenunga, Unley, Marryatville, Norwood Morialta, there is an increasing population in those areas and it’s a huge pressure but it’s not to say there aren’t pressures in other areas and as we get advice from the department we will frame our response.”

He didn’t confirm or deny whether the project would be funded in the upcoming budget and denied his Government had been undermined by the leak.

“Just because Labor claims something, I think there needs to be a little bit more rigorous investigation as to whether or not that was the case,” he said.

“What we saw under the previous government over a long period of time were pet projects around marginal seats and electoral cycles.

“What we’ve done is establish Infrastrucutre SA which provides that independent evaluation so that when we’re spending money it’s done against a set of independently-verified criteria.

“That’s exactly the process we’ve set up. It’s very open and transparent. They publish their report every year and I just encourage people to take a look.”

Australian Education Union state president Lara Golding said “we would welcome additional much-needed investment in public education” but questioned how the decision had been made for the location of the school.

“Given the high level of need for capital works funding for schools and preschools across the state, the community deserves to know how decisions on funding are made,” she said.

“How has the community been consulted on this decision and where is the transparency?

“Earlier this year, the Education Chief Executive talked about the need for a new school in the inner north, and schools and preschools around the state need funding for building maintenance and upgrades.

“Minister Gardner must provide the public with demographic modelling across the state and explain why his electorate has a greater need for a new school than other areas of the state.”

Treasurer Rob Lucas said “this is just one of many requests for funding we get each year in the lead up to the State Budget”.

“It is not a Cabinet document, it has never been to Cabinet – it’s a document that agencies use in discussions with the Treasurer in preliminary Budget discussions,” he said.

“As published in March, the independent infrastructure advisory body, Infrastructure SA, has recommended an investment decision for a Rostrevor high school in the near-term having demonstrated a well-progressed business case – its only recommendation in relation to a new school.

“The Government’s final decision on this and other funding proposals will be revealed when the State Budget is handed down in less than a fortnight.”