The Reagan administration has underestimated its projected deficit for next year by $22 billion and will fall $49 billion short of its goal of a balanced budget in 1984, according to projections made by the Congressional Budget Office for its soon-to-be-released annual report.

Using different economic and program assumptions from the administration's, the independent budget arm of Congress concluded that the federal deficit for fiscal 1981 will be $67 billion, or $22 billion more than the $45 billion that the administration forecasts.

For fiscal 1981, which began last October, CBO estimated a deficit of $63 billion, $8 billion more than the administration's forecast of $55 billion.

Looking ahead to 1984, when the administration has said it will present the country with a $1 billion surplus, the first black-ink budget in 15 years, CBO projected a deficit of $49 billion.

The report is to be released by CBO Wednesday. Its summary table was obtained yesterday from sources outside CBO.

CBO's report is likely to rekindle the debate over the administration's assumption that its economic program, including large-scale tax and spending cuts, will have a profound effect in curbing inflation and stimulating the economy. CBO is essentially assuming less rosy results than the administration.

When a preliminary CBO analysis of administration spending estimates leaked out last week, President Reagan first called them "phony" and then backed off, saying they amounted to differing expectations about the impact of his economic program.

The CBO deficit estimates came to light as congressional committees continued to hear from agitated groups whose programs would be affected by the Reagan budget cuts.

In the Senate Finance Committee, a doctors group appeared in support of Professional Standards Review Organizations, which police hospital admissions and other medical practices under Medicare and Medicaid. Reagan wants to kill the program.

The Senate Committee on Indian Affairs heard Wendell Chino, president of New Mexico's Mescalero Apache tribes, say cuts in Indian programs would "bring programs among the Indians to a halt . . . set the tribes back 30 to 50 years."

Angry Democrats on a House education subcommittee said they would not tolerate the president's "freeze" on processing of 1 million applications for college student grants and demanded that Secretary of Education Terrel Bell cite legal authority for the holdup of federal work on the applications. "Obviously, when I get an order from the president I comply with it," declared Bell.

Amtrak President Alan S. Boyd again asserted in Senate testimony that the cuts proposed in his budget would mean the end of rail passenger service outside the Northeast, prompting Sen. Mark Andrews (R-N.D.) to declare that if that were so, Congress might prefer "to kill the whole snake" and abolish Amtrak.

The House Democratic Study Group added its voice to the mounting Democratic chorus of criticism of the Reagan budget cuts, saying the administration is wrong in claiming that its spending cutbacks are distributed fairly.

With roughly three-quarters of the budget shielded from the budget ax, "it will be middle- and lower-income Americans, in particular the working poor, who bear the brunt of these [Reagan's] cuts," said DSG, a research group that courts most House Democrats as members. The cuts, added DSG in a report on the budget, 'would be particularly harmful for the working poor -- those with jobs who rely on small amounts of federal support." CAPTION: Picture, Kentucky Lt. Gov. Martha Layne Collins and Govs. Fob James of Alabama, William Winter of Mississippi and Lamar Alexander of Tennessee listen to testimony at House panel session on the Tennessee-Tombigbee Waterway. Its completion has been put in doubt by a Senate committee's vote to halt construction on the $2 billion canal. By James K.W. Atherton -- The Washington Post