Tanya Plibersek concedes Australia’s long-running blueprint to return environmental water to the mighty Murray-Darling Basin is in peril and the consequences of not getting it right will be dire.

“This a plan that is in trouble, deep trouble, and the next drought is just around the corner,” the federal environment minister told ABC radio.

“If we don’t get this right, the environmental impacts are serious.”

Ms Plibersek said there were three million people who relied on the river system for drinking water and some 30 threatened animal species living across the region.

“We know the psychological, the social toll it took. We had towns that had bone dry river beds for over 400 days during the last drought,” she said.

“We need to get it right for the sake of our environment and the sake of our communities and we’ve left it way too late under the previous government.

“We’ve got to get our skates on.”

A new deal ensuring promised water under the Murray-Darling Basin Plan will be returned to the environment, but over a longer period, was announced on Tuesday.

The timeline to recover 450 gigalitres of water earmarked for the environment has been pushed out until the end of 2027 and water infrastructure projects until the end of 2026, after the initial June 2024 target was on track to be missed.

The new plan – which limits the amount of water extracted from the basin – includes more options and funding to deliver the remaining water, such as through voluntary buybacks.

The 12-year plan to restore the nation’s largest and most complex river system, which runs through four states and dozens of towns and cities, was created in 2012 after years of overuse and the devastating millennium drought.

The Murray-Darling Basin Authority has previously advised there would be a shortfall of 750 gigalitres – about one-quarter of the target – by June 2024.

Ms Plibersek said on Tuesday the agreement struck between the federal and NSW, South Australian, Queensland and ACT governments came at a crucial time with drought looming.

“What we’re proposing is more time, more money, more options and more accountability,” she told reporters in Sydney.

The minister said voluntary water buybacks would complement the infrastructure projects and that all options remained on the table.

Victoria, which has previously opposed water buybacks, is the only basin government that hasn’t signed up to the new plan.

Ms Plibersek said her door remained open and there were significant benefits for the state to sign.

She refused to speculate about the details of the water buybacks – such as how much money would be made available – as it had the potential to distort the market.

– AAP