TALLAHASSEE, Fla. (AP) _ A circuit judge Friday upheld major provisions of a new Florida law designed to control the soaring cost of commercial liability insurance.

The law, which went into effect July 1, rolled back rates to 1984 levels and limited jury awards to $450,000 for such non-economic damages as pain and suffering.

Three trade organizations and more than 280 individual companies sued seeking to have the Tort Reform and Insurance Act of 1986 declared unconstitutional.

Lengthy hearings were held in the case in August and September.

Judge Charles Miner issued the 44-page opinion after weeks of studying the arguments.

''Florida law was more comprehensive than that of any other state, and yet it stood the test in an all-out legal assault,'' said state Insurance Commissioner Bill Gunter, a defendant in the suit.

The law was aimed at helping businesses such as day-care centers that have had difficulty finding affordable liability insurance since rates began to climb in the early 1980s.

The insurance industry had maintained that the new law interfered with its right to earn fair profits and argued the law attempted to pull too many unrelated areas of insurance law together into a sweeping package of reforms.

The judge did strike down as unconstitutional a requirement that insurers refund to commercial liability policyholders 10 percent of the cost of policies issued before July 1, when the law went into effect.

The rebates still would apply to policies issued or renewed after July 1.

Tom Maida, a lawyer for the plaintiffs, said the 10 percent credit for all policyholders had been expected to cost insurance companies $140 million. Since 70 percent of policies were dated before July 1, he said, the ruling saved the insurance industry about $98 million. ''It's certainly not a total victory. It's a partial victory. The insurance companies will be pleased with the fact that they won't be required to regurgitate these millions of dollars, but they certainly wanted more in this lawsuit,'' Maida said.

An appeal of the ruling is expected.

A number of insurance companies announced after the law went into effect that they would not write any new commercial liability policies in the state until the matter had been decided in court.