TORONTO, DEC. 11 -- The Canadian government today announced a $3 billion program to clean and protect the country's air, water and land over the next five years, calling it the most comprehensive environmental plan in the world.

The plan, the product of more than a year of intense battles within Prime Minister Brian Mulroney's cabinet, includes what Environment Minister Robert De Cotret said are more than 100 initiatives involving 40 federal agencies.

The program seeks to reduce air pollution by 40 percent over the next decade; create five new national parks; clean up the Great Lakes and other waterways; stabilize carbon-dioxide emissions at current levels by the end of the century; reduce solid waste in municipalities and provinces by 30 percent and use the army to contain disasters such as oil spills. The plan also commits millions of dollars to stemming global warming; eliminating toxic discharges by industries; protecting the Arctic; promoting energy efficiency and passing and enforcing laws to ensure safe drinking water.

The parliamentary opposition and environmentalists criticized the plan as vague and lacking in assurances that the $3 billion allocated to it actually will be spent. The government is struggling to curtail a $30 billion budget deficit and the environmental plan still will face a program-by-program review by the cabinet and the federal Treasury Board.

Critics said the plan is designed to improve Mulroney's popularity before the 1993 national election.

"This is the kind of ploy that has made Canadians very cynical about politicians. This a public relations document. We ought to be doing this because we love the planet, not because there is a decline in the polls," said Paul Martin Jr., environment specialist for the opposition Liberal Party.

David Runnalls, an environmentalist with the Institute for Public Policy, said many of the promised programs fall under the jurisdiction of the provinces, which may not implement what the central government is promising.