Confident that Congress will soon give him the power he requested to reorganize the federal government, President Carter has approved a basic blueprint for an attack on bureaucracy "from the bottom up."

The plans were outlined in an interview yesterday by Harrison Wellford, executive associate director for reorganization and management of the Office of Management and Budget, 24 hours after Carter had approved them at a meeting with Wellford and OMB Director Bert Lance.

Wellford said the basic decision was to move ahead with a few short-term projects "that can get results," while launching a government-wide review of problem areas that might be tackled over the next four years.

The first of the "crash" programs, involving the Executive Office of the President, is "well under way," Wellford said, and should be ready to go to the President within three months.

Under the reorganization authority sought by the President, a reshuffle of the executive office and the executive branch would take effect automatically unless vetoed by the House or Senate within 60 days.

The Senate has already passed the bill giving the President that kind of reorganization power, and a House subcommittee is expected to approve it before the end of this month.

The House Appropriations Committee has given Wellford 32 additional employees, at an annual cost of about $2.6 million to work on reorganization plans. Wellford said the project would also draw heavily on career employees in OMB and government agencies and perhaps some volunteers from private business as well.

When he testified two weeks ago for the additional jobs, Wellford told House members that reoganization is "going to be a four-year effort at least." He added in the interview that the President will "do a lot of structural reorganization where it's appropriate.

"But," Wellford said, "we'll do it from the bottom up - not apply a set of abstract principles from the top down. We'll get our clues from the failures at the program level. We'll do a government-wide survey of our program problems, and the zero-base budgeting the President has ordered for the next year will help in that process, too."

In his testimony, Wellford said the reorganization squad will split into six teams, reviewing programs in natural resources and energy, economic development, human development, national security and international affairs, general government and government regulation.

During the campaign, Carter said repeatedly that the 1,900 agencies of government should be cut back to not more than 200, as he had consolidated agencies during his term as governor of Georgia.

Wellford, in testimony, said that "if we can increase the competence and efficiency of government by reducing it to 200 (agencies) we will do it . . . But we'll need to find out where the waste and duplication is before I can tell you precisely where we're going to come out."

However, he said that his team was already studying the 1,200 advisory commissions and committees in government and would move quickly to kill the ones that aren't necessary.

In the interview, Wellford said heavy stress would be placed in the reorganization effort not only on consolidating and transferring functions, but on improving management and expanding communications with other levels of government and outside citizen groups.

He revealed, in passing, that the principal management tool of Ford administration OMB Director James T. Lynn, the so-called A-113 Circular, had been suspended by Carter and Lance.

Lynn's "Presidential Management Initiatives," aimed at cutting paperwork and improving efficiency in the departments and agencies, had "some good ideas but was not being well-implemented," Wellford said. "The paper it was generating wasn't yielding much policy insight."

Wellford, who will be 37 later this month, is the holder of a Harvard Ph. D. and Georgetown University law degree. He was a public-interest lawyer and served as legislativeassistant to the late Sen. Philip A. Hart (D-Mich.)