Substantial pay raises -- some in excess of $20,000 per year -- will be proposed today for many of the government's top elected and appointed officials by a blue-ribbon task force that has been studying U.S. government executive salaries for the president. President Carter is expected to ask for an executive-legislative-judicial pay increase in his final budget to Congress next month, althouth the law permits him to raise, lower or ignore the task force recommendations.

The salary increases, first in four years for many of the government's senior level officials, would have to be approved, they would go into effect in the first days of the Reagan administration.

The recommendations will be made by the Commission on Executive, Legislative and Judicial Salaries. The blue-ribbon task force, known as the Quad Com because it meets by law every four years, says that the government will face major problems recruiting and retaining the best people unless the people chosen to run it are given substantial raises immediately.

This lame-duck Congress has been wrangling for the last two weeks over a much more modest proposal, to raise top federal and congressional salaries by around 17 percent. That figure represents the compounded amount of the last two pay raises that went to rank-and-file civil servants -- raises that a politically gun-shy Congress refused and refused to allow for U.S. officials making $50,112.50 or more.

Although the Quad Com report addresses the salary situation of only a few thousand members of the executive, legislative and judicial branches of government, the effect of any pay raise for cabinet officers and members of Congress would be to lift the ceiling for members of the Senior Executive Service and other workers -- about 30,000 in total -- who now are frozen at the $50,112.50 pay level.

Aides to President-elect Ronald Reagan have been working behind the scenes to get some sort of pay raise for top-level federal officials on the books before he takes office. Four years ago President Gerald Ford recommended similar high-level pay raises for incoming members of the Carter administration.But the rules have changed since then.

The Quad Com originally was set up to take the political sting out of top federal pay raises. Its recommendations, subject to modification by the president, went into effect automatically unless vetoed by Congress. That law was changed a couple of years back. Now members of the House and Senate -- unless some way can be found around it -- will have to go on record as favoring or opposing any 1981 raises. That has proved a problem in recent weeks. Congressional adjournment, and funding of key federal operations, was delayed as Congress hassled over a proposed $10,000 raise for itself. Many opponents of the 17 percent pay increase worked via the committee and budgetary route to make the raise automatic, so they could vote against them and still get them. Record votes on pay raises are not popular.

If a lame-duck Congress was afraid to give itself a 17 percent catchup raise, many wonder if the new more conservative Congress will have the courage to okay proposals for boosts of 25 percent and more if they have to do it in a record vote. There is a chance congress will go along with the new rates -- although President Carter is expected to scale them down somewhat -- if he and incoming President Reagan jointly urge legislators to bite the big bucks bullet and hope things quiet down before the 1982 elections. b