The Victorian premier, Ben Carroll, has made an about-face, committing to pushing ahead with the first stage of the Suburban Rail Loop while promising to reduce its total cost by about 6%.

He will also announce changes to the scope of the first stage of the project on Tuesday , known as SRL East – a 26km stretch of tunnels between Cheltenham and Box Hill – estimated to save $1bn, and an “independent, technical review” to identify a further $1bn in savings.

The Suburban Rail Loop Authority, which is the statutory agency responsible for planning and delivering the project, will be folded into the Victorian Infrastructure Delivery Authority. The move was already under way prior to Carroll becoming premier four weeks ago.

No further contracts will be awarded until the review is complete but the government has stressed all current works will continue, with tunnelling between Burwood and Glen Waverley set to begin soon.

Prime Minister Albanese will seek to use Wednesday’s high-stakes talks with premiers to quell growing unhappiness about national controls on datacentre developments, promising new approval laws will complement state rules.

With potential to be one of the major reforms of Labor’s second term, the new law will set tough copyright rules for AI businesses and impose standards for security, safety and skills development.

The industry’s rapid growth, driven by increasing reliance on AI and cloud computing, remained one of the most significant causes of growth in electricity demand, according to Aemo’s annual Electricity Statement of Opportunities. The Climate Council chief executive said datacentres were set “to devour an enormous share of Australia’s electricity in the coming years”.

Albanese will use the national cabinet to strike agreement on a plan to legislate nationally consistent minimum obligations for datacentres, requiring them not to push up energy prices, meet their own infrastructure costs and minimise water use. The rules will also require developers to minimise the effect of new datacentres on local communities, ensuring they are appropriately sized and appropriately located, away from homes, schools and potential housing or agricultural sites.

More than 270 leading marine scientists from 84 research institutes have written to the environment minister, Murray Watt, urging stronger protections for marine ecosystems, as a once-in-a-decade review of marine parks gets under way.

The director of the Marine Futures Lab at the University of Western Australia and an author of the statement sent to Watt, said many species found in Australian waters existed nowhere else on the planet. About a quarter of Australian waters are currently highly protected. But these “no take zones” were concentrated in remote offshore and territorial waters, with minimal coverage in the waters surrounding mainland Australia, the statement said. While the director of the Centre for Biodiversity and Conservation Science at the University of Queensland said the current locations of highly protected areas were “biased towards places that no one goes”.

Watt said the government was “well on the way to meeting the Albanese government’s commitment to highly protect 30% of Australia’s ocean by 2030”, and the proposed expansion of marine parks around Lord Howe and Norfolk islands would achieve the target ahead of time. The marine parks review would provide “further opportunities to better protect key ocean habitats”, he said, “while allowing for sustainable use and conservation”.