The issue is coming to a head as the Patrick administration battles insurers over swiftly escalating rates they have been charging small employers. In February, the governor filed sweeping legislation that proposes to give the Division of Insurance the power to essentially cap health care price increases. That proposal is still pending.

“Those employers are trying to keep their doors open, and to the extent they can cut expenses, they will cut health insurance because they know their people can go to Commonwealth Care,’’ said Mark Gaunya, president of the Massachusetts Association of Health Underwriters, a trade group representing more than 1,000 brokers and other insurance professionals.

But insurance brokers say the pace of terminations has picked up considerably since then among small companies, of which there are thousands in Massachusetts. Many of these companies — restaurants, day-care centers, hair salons, and retail shops — typically pay such low wages that their workers qualify for state-subsidized health insurance when their employers drop their plans.

The Massachusetts Division of Health Care Finance and Policy annually surveys employers and found no significant drop in coverage as of the end of 2009, when more than three-quarters of companies offered health insurance.

State officials said they have not seen convincing evidence that there is a trend. There has not been an unusually large spike in enrollment in Commonwealth Care, the subsidized insurance program, according to spokesman Richard Powers. And in any case, Dr. JudyAnn Bigby, secretary of health and human services, said the administration budgeted for higher health care spending because it anticipated that there would be growing numbers of long-term unemployed residents who would be signing up for coverage.

Precisely how many small businesses have recently given up offering insurance is hard to pinpoint. The Office of Labor and Workforce Development said the most recent quarterly insurance data collected from small companies has not been compiled.

“They are giving up out of frustration,’’ Fields said of the employers. “Most of them are very compassionate but they simply can’t afford health insurance any more.’’

In Sandwich, business consultant Bill Fields said he has been hired by small businesses to enroll about 400 workers in state-subsidized care since April, because the company owners said they could no longer afford to provide coverage. Fields said that is by far the largest number he has handled in such a short time.

Since April 1, the date many insurance contracts are renewed for small businesses, the owners of about 90 small companies terminated their insurance plans with Braintree-based broker Jeff Rich and indicated in a follow-up survey that they were relying on publicly-funded insurance for their employees.

The relentlessly rising cost of health insurance is prompting some small Massachusetts companies to drop coverage for their workers and encourage them to sign up for state-subsidized care instead, a trend that, some analysts say, could eventually weigh heavily on the state’s already-stressed budget.

And on April 1, exercising authority the administration had never before used, the division denied 235 of 274 increases proposed by insurers for plans covering individuals and small businesses — base premiums would have increased as much as 32 percent. On July 1, it again held 137 proposed increases to 2009 rates.

The sides have been locked in negotiations for months, with the Patrick administration recently reaching agreement with two insurance carriers on lower rates.

“The Patrick-Murray Administration has taken decisive action to provide small businesses and working families with immediate relief from skyrocketing health insurance premiums,’’ the governor’s press secretary, Juan Martinez, said in a statement. He declined to directly address whether small businesses are increasingly dropping health coverage and directing their workers to subsidized care.

But analysts said the burden of double-digit insurance increases shouldered by small businesses over the last several years is likely to become more of a public problem.

“The more the employer insurance system unravels, the higher the cost is going to be for the state in providing subsidies to low income workers,’’ said Larry Levitt, vice president of the Kaiser Family Foundation, a California-based think tank. “From a state finance perspective, stabilizing employer insurance is definitely important.’’

The state’s landmark 2006 health insurance overhaul included regulations designed to discourage low-wage employees from opting for state health insurance over their companies’ often more pricey coverage. It denied eligibility to any one whose employer had offered him or her coverage in the past six months and paid at least 33 percent toward the individual’s plan.

Most health care advocates and brokers had widely interpreted that to include even workers whose companies had dropped coverage. But recently, some companies that have terminated their group plans have tested those waters and found that their employees were accepted for state-subsidized coverage.

Additionally, company owners say, it has become far cheaper to pay the state penalty for not covering their workers — roughly $295 annually per employee — than to pay thousands more in premiums.

In New Bedford, the Early Learning Child Care center is now paying $1,500 quarterly in fines to the state, instead of the $30,000 it contributed quarterly toward 13 workers’ health insurance premiums. When Executive Director Judy Knox terminated the company’s health plan late last year, she asked Fields, the consultant, to help 10 of those workers enroll in Commonwealth Care. The other three went on spouses’ plans or were eligible for Medicare.

“We had had, in the three previous years, between 17 and 18 percent increases every year,’’ Knox said. “I was so worried about the staff and their coverage, but for most of them, Commonwealth Care seems to be working out very well.’’ The state program covers people with incomes up to 300 percent of the federal poverty level.

Come 2014, when the bulk of the federal health care law goes into effect, the penalties for small companies that do not provide health insurance coverage will be less onerous than those in Massachusetts. That could tempt more small companies to opt out nationally, sending more workers to the public rolls — if health care costs can’t be restrained, some analysts said.

“Struggling business don’t necessarily feel the need to offer coverage to attract workers,’’ said Kaiser’s Levitt.

Massachusetts has not decided whether to adopt the federal rules for small businesses.

The federal law does not impose any penalty on companies with fewer than 50 employees that do not offer coverage, whereas in Massachusetts, employers with more than the equivalent of 11 full-time employees face fines for not offering a health plan and contributing at least 20 percent toward that coverage. But for companies with more than 50 workers, the federal law comes down a lot harder than does the state law.

Kay Lazar can be reached at klazar@globe.com.

© Copyright 2010 Globe Newspaper Company.