Massachusetts' first step towards universal health care insurance may be a first step towards a national health care plan, says Gov. Michael S. Dukakis.

"What we do here today can and must be done all over the United States," the Democratic presidential front-runner said Thursday, signing the nation's first law to make health insurance available to all Bay Staters by 1992."We have made a great start," he told about 2,000 supporters crowded onto the Statehouse steps for the signing ceremony. "Now we must make it work. And then we must carry the message of health care for all across all this country."

Dukakis said universal health care was under discussion in Massachusetts for nearly two years before it passed the Legislature, it has been 40 years since Harry S. Truman proposed it for the nation.

"As an American, I don't want my country to stand alone with South Africa as the only two industrialized nations that do not provide basic health security for their citizens," Dukakis said.

Dukakis supports a bill by Sen. Edward Kennedy, D-Mass., calling for minimum health care guarantees "as the first step towards providing health insurance to all Americans," said Dukakis campaign spokesman Steve Akey.

The governor also supports states taking their own initiative to offer universal health care, Statehouse press secretary James Dorsey said.

The Massachusetts bill was the outcome of a nine-month legislative struggle and comes two years after Massachusetts voters voted 2-1 for a non-binding referendum urging Congress to enact a national health care program.

Dr. David U. Himmelstein of Harvard Medical School, spokesman for Physicians for a National Health Program, called the health care bill a first step but "a Band-Aid approach when major surgery is needed."

On Wednesday, Dukakis estimated that the law's cost to taxpayers would be $645.2 million through fiscal 1992, less about $22.5 million in projected cost-cutting in Medicaid. Other estimates put the cost to the state government in the next four years as high as $1.2 billion.

The law would provide coverage to about 600,000 Massachusetts residents under age 65 currently without health insurance, or roughly one of every 10 people in the commonwealth.

This would be done in stages and through a variety of approaches, from extending Medicaid benefits for disabled adults and children to state-brokered, pooled insurance for small businesses and individuals.