The Reagan administration, in conjunction with Sen. Paul Laxalt (R-Nev.), is on the verge of supporting regulatory reform legislation that includes a controversial measure extending the power of federal courts to oversee federal rulemaking activity.

The legislation is expected to be introduced next week by Laxalt, with the support of Vice President George Bush, head of the administration's regulatory reform task force.

The court powers section of the bill is an adaptation of the so-called Bumpers Amendment, which is named for its original author, Sen. Dale Bumpers (D-Ark.). It would prohibit courts from presuming that an agency's interpretation of its enabling statute is correct, permitting judges to substantially study the basis for a new federal rule.

Although the bill is less stringent in forcing agencies to adopt a strict cost-benefit analysis in issuing new rules than an earlier draft of the Laxalt plan, it goes much further than Democratic-sponsored measures now before the House and other proposals hotly debated last year by two Senate committees.

Perhaps more importantly, the bill makes clear the importance of agencies taking seriously the controversial cost-benefit analyses, a provision likely to add to labor and health group opposition to the measure.

The bill has dropped from an earlier draft version a section expanding the power of the Office of Management and Budget to monitor agency compliance with the legislation. Curiously, it also would not become effective until Jan. 1, 1983, two years after the Reagan administration took office.

Under the legislation, agencies issuing major regulations, defined as rules with a compliance cost of at least $100 million or with a substantial effect on consumer prices or employment, would be required to provide a detailed compilation of the quantifiable costs and benefits.

The legislation also would require agencies to review all major regulations every 10 years to determine whether they should be killed or rewritten. Further, the legislation requires agencies to publish a semiannual agenda of regulatory actions.

In most significant ways the legislation is parallel to the administration's executive order on regulation.