The Canadian government today predicted the nation's economic output will plummet by 4.4 percent this year, a sharp downward revision that confirms the severity of the recession here.

Responding to severe criticism of its handling of the economy, the Liberal government abandoned a handful of controversial tax proposals and announced an $800 million program to create 475,000 jobs, and a plan to stimulate the housing industry.

As recently as June, Canada's gross national product this year was predicted to fall less than 2 percent.

The decline now expected is staggering, measured against economies in the Western industrial nations. By comparison, Great Britain's GNP fell 2.2 percent in 1981, and this year the U.S. gross national product is likely to fall about 1.6 percent.

In a gloomy economic statement, a spokesman for the government of Prime Minister Pierre Trudeau said inflation, now at 10.4 percent, would not moderate until next year, and unemployment, now at 12.2 percent, would remain close to that level through 1983.

Finance Minister Marc Lalonde also told members of Parliament that, because the unexpectedly severe recession had reduced federal revenues, the deficit in the year ending March 31, 1983, would reach $18.3 billion from $8.2 billion predicted less than one year ago.

The jobs program is intended to create employment in rail construction, the housing industry and other sectors. About 1.4 million Canadians are out of work among a labor force of 11.9 million.

Another $150 million will be spent on housing, including grants for purchases of new houses started between next Jan. 1 and April 30. A new $250 million-a-year tax measure would allow investors to defer a portion of capital gains on common stocks held in publicly traded Canadian companies.

The government said growth would pick up in 1983 to the 3 percent level. Lalonde urged Canadians to cooperate with the voluntary wage and price restraint program initiated in June, which he said had already helped to start a declining trend in the rate of consumer price rises.

Lalonde did not offer any quick or easy solutions to the country's problems. "The worldwide recession has cut our economy to the bone," he said. "We have lost half a million jobs during the past year."