The energy budget will shrink by more than $1 billion, largely due to the government discontinuing its $250 power saving bonuses, but biodiversity and land management funding has also been slashed.

The 2023-24 environment and biodiversity budget is down 23 per cent from its 2022-23 target and 55 per cent down on the 2021-22 actual spend.

The land management budget, which cares for Victoria's forests, coasts and crown land, is also down 23 per cent from 2022-23 and 41 per cent from 2021-22.

Western Victorian Greens MP Sarah Mansfield said the cuts were disappointing, but didn't come as a surprise.

"This was something we were worried about coming into the budget because we heard there would be big cuts and it looks like there's been about $2 billion of cuts to the environment department and the programs run through that department," Dr Mansfield said.

She said environmental problems in the south-west, and throughout the state, were only getting worse, so it was perplexing to see funding going down.

"We've got an extinction and biodiversity crisis, we've got the impacts of climate change already being felt and we already don't put enough money into the environment," she said.

"So we should be seeing more money and instead we're seeing cuts."

Waterway management funding is up more than 50 per cent from 2022-23, but the rise is almost entirely due to federal funding and ongoing flood recovery efforts.

"Water again is very disappointing," Dr Mansfield said.

"One of the largest parcels of (state government) money in there is being put aside to turn a reservoir into an angling and boating recreation area. It's questionable whether that's money for water in the sense most people would imagine."

She said a $10 million investment in waterway revegetation was important. "Whether it's enough is another question and it doesn't look like there's any new spending on what's needed for our rivers."

Funding for coastal care projects appeared to be steadily declining, with participation targets for the decades-old Coastcare program down by 30 per cent.

Warrnambool environmental activist and founder of Beach Patrol, Colleen Hughson, said the cuts were worrying especially combined with the lower volunteer targets.

"It's quite frightening if they're reducing the money going into the environment while also reducing volunteer numbers," Ms Hughson said. "There's always been a massive reliance on volunteers to do the bulk of the work down here."

She said the stretch of coastline from Warrnambool to the South Australian border had always had the fewest Parks officers.

"They're so stretched and that's been the case for the past couple of years, so if that's going to reduce even further then it's pretty terrifying," she said.

"Our environment is being decimated and the government isn't taking it seriously. Meanwhile they have tendered out our whole coastline to gas companies."

A spokesperson said since 2014 the Andrews government had "invested $582 million in biodiversity and $150 million on coastal projects, delivering significant outcomes for our land and coastal environments". The spokesperson said the cuts to the biodiversity budget didn't take into account $60 million in "ongoing" funding.