The federal government's omnibus budget legislation includes a "serious attack" on environmental law, a university professor says.

The bill, which was introduced Thursday in the House of Commons, repeals the Kyoto Protocol Implementation Act and outlines major changes to the environmental assessment process.

Those changes include setting timelines for assessment hearings, transferring assessments to the provinces and consolidating the process in three government agencies.

Furthermore, under the proposed changes the cabinet would have authority over oil and gas pipelines projects, and the Fisheries Act would only apply to major waterways.

The bill is "a serious attack on environmental law in this country," environmental lawyer and University of Ottawa professor Stephen Hazell told CTV's Power Play.

"What they're doing to the Fisheries Act is taking a law that took the Mulroney government five years to pass…and they've replaced that with discretion."

Hazell said the changes could result in far fewer environmental assessments.

"We may not have any environmental assessments at all at the end of the day coming out of this whole process," he said.

The bill also outlines tougher monitoring and inspection strategies, proposing higher fines for those who contravene industry regulations.

But according to Hazell, such measures are "very small beer in the context."

"The context is there used to be several thousand environmental assessments being done every year; now there's going to be a small handful," he said.

Finance Minister Jim Flaherty said the purpose of bundling the policy changes into the budget bill is to speed up the process of getting it into law.

But Hazell suggested the government has other motives.

"They don't really want to talk about what's there," he said." I think they want to get this through the House very quickly."

Some critics are calling for the environmental policy changes to be separated out into another bill, which would allow experts to study their impact.

"It is an affront to democracy to bury such far-reaching changes to laws Canadians depend upon to help protect our environment in the budget implementation bill in order to avoid public scrutiny," Greenpeace spokesman Keith Stewart told The Canadian Press.

"Changing the rules to favour the oil industry will only fuel the growing opposition to projects like Enbridge's proposed tar sands pipeline through British Columbia."

Green Party Leader Elizabeth May on Friday called the bill "420 pages of omnibus abuse of parliamentary process" and asked the Primer Minster Stephen Harper to "separate out bills that matter to the environment."

If the environmental process changes, Hazell said, "there are risks of major catastrophes" like a tailing dam failing along the Athabaska River in the oilsands region, which would mean "literally hundreds of thousands of tons of toxic sludge are going to roll down that river."