Labor has declared the Turnbull government's changes that slash the size of Australian marine parks are scandalous.
The opposition failed in an attempt to shoot down the changes to 44 Australian marine parks covering 3.3 million square hectares, with the Greens regrouping to lobby crossbenchers for another attempt.
The plan reduces 'green' conservation areas in the Coral Sea from 50 to 25 per cent, giving five million recreation fishers greater access to park waters.
"What the government is doing on marine parks is scandalous," Opposition Leader Bill Shorten told reporters in Canberra on Wednesday.
"It's one of the largest withdrawals of environmental protection that we've seen in Australian history."
Labor urged crossbenchers to consider the impacts to the environment.
The Greens claim the government's plans mean Australia will be setting the lowest conservation standards in the world if the changes are allowed to stand.
The minor party will work with Labor on another disallowance motion after the failure of their first attempt.
The federal government brought on the motion on Tuesday evening - weeks earlier than expected - in a move which the opposition claimed denied them time to lobby crossbenchers for support.
"Now that tax cuts have been taken off the agenda we've got plenty of time to talk to the crossbench about why it's a bad idea to allow these management plans to go into law," Greens senator Peter Whish-Wilson said.
"The standard you walk past is the standard you accept. We can't accept this as the standard for marine protection in this country."
Consultations over the past five days with environmentalists, scientists and community campaigners revealed they didn't want the changes, the Greens say.
But government frontbencher Anne Ruston said the reforms are based on scientific evidence and consultation with all legitimate stakeholders.
"It contrasts starkly to the purely ideological approach taken by the former Labor government to lock Australians out from their own oceans. We have maintained the right to fish," she said.
"The reforms constituted a genuinely balanced approach to the sustainable management of Australia's marine resources and the environment."