BALTIMORE, JAN. 7 -- Top Maryland union officials and business leaders announced yesterday that they will lobby the General Assembly to pass legislation designed to curb the state's rising health care costs.

The major proposal being pushed by the leaders is creation of a commission to study the cost of Maryland's non-hospital medical care.

They also propose studying whether certain medical specialists should be regulated, enacting legislation that would allow insurers to offer "basic benefit" health packages to companies and individuals who now have no coverage and requiring doctors to tell patients if they have a financial interest in the medical laboratory being used.

"Those are certainly issues that are worth a good, hard look," said Nelson J. Sabatini, deputy secretary of the state's Department of Health and Mental Hygiene.

The legislative proposal was drafted by a 10-member ad hoc committee of leaders of the state AFL-CIO and Maryland Chamber of Commerce concerned about the increasing cost of premiums for employee health plans.

In a report released yesterday, the committee noted that Maryland's per capita health care costs were slightly above the national average in 1989 -- $2,436, compared with $2,425 nationally.

Committee members said they are perplexed by the Maryland figure because the state's hospital care costs are 9 percent below the national average.

"That made us realize that something was happening in the non-hospital sector," said Ernie Crofoot, a member of the ad hoc committee and Health Care Committee chairman of the AFL-CIO.

The commission that would be established by the committee's suggested legislation would examine private physicians' fees and practices, committee members said.

"We just want a better sense of what's going on out there," Crofoot said. The commission's report "could easily show that what they're doing is right."

Committee members said they expect specialists and other doctors to battle two bills that would regulate their fees and practices.

One bill calls for the state's Health Services Cost Review Commission to study the rates of hospital specialists, such as radiologists and anesthesiologists.

Another bill would force physicians to inform patients when they are being sent to a lab owned by the doctor. The committee report cited a 1989 study showing that doctors who own X-ray machines take four times as many X-rays as those who send patients to specialists.

"You're going to have the doctors saying, 'Why should we give information? We're not out of line,' " said Peter J. Lombardi, chairman of the Maryland Chamber of Commerce. "And the specialists are going to say, 'Why are you picking on us?' "

The committee's legislation would allow insurance companies to offer health care plans that would exclude some of the 35 state-mandated benefits now offered in health care packages. The basic benefit plan would be offered only to individuals without health insurance and to small businesses that don't provide health care plans.