The Greens say fossil fuel companies' donations to Labor show it will be tough for the party to fully commit to renewable energy.
Bill Shorten has promised to make half of Australia's power renewable but the Greens say Labor wont give up on fossil fuels due to the donations it gets.
Data shows gas, oil and coal companies gave Labor $1.62 million over the past five years, including $641,000 from Woodside Energy.
"Climate change is one of the leading causes of habitat loss and extinction, yet the Labor Party is beholden to emissions-intensive polluters like Woodside, Santos and Chevron," Greens Senator Sarah Hanson-Young says.
"They are on the fence about Adani, split on drilling in the Great Australian Bight and are pro-fracking. And it's clear why when you look at this shocking donation data."
A coalition of environment groups will protest about coal and fossil fuels outside Labor's national conference in Adelaide on Sunday.
"The Great Australian Bight whale nursery is a completely inappropriate place for risky deep sea oil drilling, especially as we hurtle towards catastrophic climate change," Wilderness Society's Peter Owen said.
Maritime Union of Australia WA assistant secretary Danny Cain said it's time for Labor to recognise the need to move away from fossil fuels to renewable energy sources.
"Our members are at the forefront of this change," he said.
"The employment shift must involve a just transition for workers in fossil fuel industries to real union jobs in new, safe renewable industries."
Labor's national conference will debate tackling climate change and securing the nation's energy future on Sunday afternoon.
Opposition Leader Bill Shorten has already promised 50 per cent renewable energy by 2030, and has announced a $15 billion plan to drive new clean energy projects and strengthen the energy grid.
He's also promised to subsidise 100,000 household batteries if Labor wins the next federal election.