The government's budget implementation bill introduced today contains the sweeping changes to environmental reviews that were announced last week as well as other "major legislative changes," according to Finance Minister Jim Flaherty.

At more than 400 pages, the bill is packed with measures contained in the March budget, including allowing for changes to the eligibility age for the Old Age Security and Guaranteed Income Supplement benefits.

Flaherty acknowledged the unusual size of the proposed legislation, but said it's a large bill because it was a large budget.

"It is comprehensive, it is forward-looking, it is our government's major policy document," he told reporters.

Flaherty said the budget implementation bill, bill C-38, contains long-term changes that are important and need to be made quickly. He also indicated that a second budget implementation bill will be just as large.

"We did as much work as we could to get as much as we could into the first act. The second act will also be quite substantial. So these are major legislative changes," he said.

Flaherty said the government is not trying to avoid public scrutiny by jamming such major changes into a budget bill, thereby avoiding specific study of the changes at individual parliamentary committees.

"The budget was very clear. We set out explicitly that which we intend to do, and I welcome public debate on it," he said.

Here's what the budget bill says when it comes to the changes the government intends to make on the environment file.

It repeals the Kyoto Protocol Implementation Act. The government had previously announced that Canada would pull out of the global agreement on greenhouse gas emissions.

It contains the changes to a number of pieces of legislation dealing with the environmental assessment process. The bill sets timelines for assessment hearings, allows Ottawa to hand off assessments to the provinces and consolidates the process in three government agencies: the Canadian Nuclear Safety Commission, the National Energy Board and the Canadian Environment Assessment Agency.

It gives the federal cabinet the authority to approve new pipeline projects and sets time limits for regulatory reviews. The changes mean if the National Energy Board disapproves of a project, cabinet can force it to reconsider.

It makes changes to how permits under the Species at Risk Act are authorized.

It overhauls the Fisheries Act to focus only on major waterways, not every single body of water, something Agriculture Minister Gerry Ritz announced Tuesday.

It sets out stiffer fines for industry players who break environmental regulations and laws.

Critics aren't happy that such fundamental changes to environment policy are contained in a budget bill and won't get the scrutiny they deserve.

"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 said in an email to The Canadian Press.