The Office of Management and Budget yesterday launched an assault on a variety of laws that it says blocks the efficient management of the federal government.

The agency sent Congress a 106-page report detailing the management changes the Reagan administration has made and what it hopes to accomplish over the next three years.

The administration says it could save more than $2 billion if its proposals for fiscal 1986 were adopted.

"While there has been some real progress in obtaining legislation that provides the incentives and the flexibility to improve the management of the federal government, some serious challenges remain," said the report, the first required under last year's Deficit Reduction Act.

"Simply recognizing that policy-making responsibility for the executive branch is shared between the occupants at both ends of Pennsylvania Avenue is not enough. Actions are needed that extend that recognition into the reality of day-to-day government operations," it added.

In the report, OMB said it would seek legislation to allow it to reorganize agencies and field offices, strengthen fraud-prevention efforts, ease procurement restrictions and further reduce regulations and paper work.

Specifically, the administration wants to:

* Renew the president's authority to propose reorganization plans that would become effective upon passage of a joint resolution of Congress.

No amendments would be permitted, and the plan would expire if not acted on within 90 days. No departments or agencies could be created or abolished under the authority.

* Remove prohibitions that limit other agencies' access to Internal Revenue Service records and records on beneficiaries of entitlement programs. Among the data bases the administration will seek to include is the Immigration and Naturalization Service's files on aliens.

* Authorize OMB to let agencies try "new and innovative" procurement methods without obtaining a waiver from Congress.

* Raise the threshold for bid solicitations listed in the Commerce Business Daily from $10,000 to $25,000.

* Authorize the hiring of private attorneys to litigate federal debt-collection cases.

* Eliminate unncessary regulations and paper work. As an example, OMB cited a rider to the fiscal 1985 continuing resolution that prohibits the agency from reviewing agricultural marketing orders, an issue that has prompted continuing debate between OMB and the Agriculture Department.

It also wants to eliminate or amend requirements for about 220 reports that agencies must now make to Congress.

President Reagan said yesterday he soon will issue a new policy statement -- perhaps as an executive order -- telling agencies to take stronger steps "to reduce waste and improve management in the federal government."

"Congress asks us to be more efficient and reduce costs -- and then prevents us from doing so," complained OMB Deputy Director Joseph R. Wright Jr. "They have an important role to play in management improvement, not by simply lending their general support but by also removing legislatively imposed barriers to good government put in place to serve limited constituencies."

A senior OMB official said the General Accounting Office, the President's Council on Management and Integrity and the Grace Commission contributed ideas about improving government management.

"We did not do this alone," said an OMB spokesman. "But we brought some form, some shape to the program."

Staff members of the House and Senate governmental affairs committees were reluctant to comment on the proposals before seeing them.

However, the House Government Operations subcommittee on manpower and housing has scheduled a hearing today on one of the proposals -- shutting down several regional offices of the Labor Department.

OMB said non-defense agencies will trim their administrative overhead costs by 10 percent -- or $585 million -- in fiscal 1986. This spending covers such areas as travel, public affairs, publications and consultants.

In line with the provisions of the Deficit Reduction Act, OMB had sought to get agencies to make similar cuts in their current budgets.

Officials reported yesterday that while civilian agencies have accepted about half of the proposed reductions for this year, the Defense Department has refused.

A senior OMB official said the Pentagon has cut its current budget for travel, public affairs and consultants by $338 million.

"They [DOD] said, 'We've taken a cut, and we're not going to do it again,' " the OMB official added. "We couldn't force them."

In addition, the administration plans an effort to contract out more civilian government functions. In fiscal 1986, agencies must review 21,500 jobs with nearly 4,300 of them scheduled to be phased out by fiscal 1986 -- a tenfold increase over this fiscal year.