Homeowners insured by a state-created property insurance program may feel ''rate sticker shock" as the insurer boosts its premiums, said the chairman of the state House Insurance Committee.

The residential Joint Underwriting Association, created after Hurricane Andrew blew away or damaged many insurers in August 1992, is planning at least two rate increases by Jan. 1. It may consider another rise next summer to ensure it doesn't have a large deficit.Committee Chairman John Cosgrove, D-Miami, was insured by the JUA for about a year before finding private coverage, after Andrew destroyed his home.

"One of the central issues that we're going to have to look at next session is rate sticker shock. How much can Floridians pay?" Mr. Cosgrove said Wednesday.

He said he is developing legislation that would reduce premiums up to 25 percent for homeowners and allow insurers to increase deductibles to 10 percent.

He said past efforts to dramatically increase deductibles would have left policyholders with hefty financial exposures. For instance, a 10 percent deductible on a $100,000 house would cost a homeowner $10,000 in a major loss.

Under Mr. Cosgrove's proposal, financial institutions could finance the 10 percent deductible as a loan. The arrangement wouldn't cost the homeowner anything, unless a major loss occurred, but it could reduce premiums substantially, he said.

"Our citizens can only pay so much," Mr. Cosgrove told the committee. ''The whole discussion about just raising rates, raising rates, raising rates - old world of insurance. We are not going to deal with the old world. We are going to deal with the new world."

Lawmakers created the JUA to provide property insurance to homeowners who couldn't find conventional coverage after Andrew. It has ballooned into the state's third-largest insurer, behind State Farm and Allstate, with more than 800,000 policies.

On Oct. 1, an average 15.5 percent increase will take effect in the JUA.

In Dade County, policyholders will pay an average of $1,161 a year on a frame house with $75,000 replacement value and a $250 deductible, according to the Department of Insurance. Private policies for the same coverage range from $428 to $1,468.

In Broward County, the average JUA policy will cost $933, while the highest private policy is $1,228. In Palm Beach County, the JUA policy will cost an

average of $864 compared to $1,077 for the most expensive private policy.

The JUA will submit another rate increase request as early as this week to take effect Jan. 1, said Jay Newman, executive director of the association. He expected the proposed average increase to be somewhat less than the 15.5 percentincrease that takes effect next month.

If private insurance rates increase sharply during the first half of 1996, the JUA probably would seek another rate increase next summer.