The wave of Cubans coming ashore in Florida could force Congress to turn this country's estimated 6 million illegal aliens into a vast new class of people who live here legally but without the full benefits of citizenship, President Carter's chief adviser on refugees believes.

In an interview yesterday, Victor H. Palmieri, the State Department's coordinator for refugee affairs, conceded that, despite the government's efforts to stem the illegal sealift from Cuba, "a very large number of Cubans" -- perhaps about 25,000 -- is going to make it to Key West or other Florida ports.

Although those arriving in the sealift are illegal immigrants and technically subject to deportation, Palmieri admitted that, as a practical matter, almost all will find a way of remaining in the United States. And, he noted, Congress then will have to find some after-the-fact way to legalize their status.

But, he continued, Congress and the nation will have to face up to "the phenomenon that is being brought to a boiling point by the Cuban influx -- the big migration waves that are being stimulated waves that are being stimulated around the world by failing economies and repressive regimes and that turn toward the United States as the land of refuge and opportunity."

Giving a special status to large numbers of illegal Cuban immigrants will prompt demands for equal treatment for other groups such as the thousands of Haitians already in Florida fighting attempts to deport them and the even larger numbers of Chinese, Vietnamese and Cambodians seeking entry, Palmieri asserted.

Eventually, he predicted, this chain reaction could extend to the Mexican-American community and cause it to insist, through leagal action and political pressure, that the exception made for the Cubans be extended to the millions of Mexicans, who are the country's largest group of illegal aliens.

The result, Palmieri said, "could confront Congress with the necessity of reassessing the entire illegal immigration problem and creating some kind of framework in which all these people could live here and work in a legitimatized status."

Because of obvious domestic political and economic problems, Palmieri said he doubted that it would be possible, at least in the first stages of such a change, to make millions of illegal aliens eligible for citizenship or even for the full range of benefits that citizens and other permanent residents enjoy.

"Since you're dealing with people at the lower end of economic scale, to do that would impose a burden of welfare and other financial costs on the government far beyond its ability to bear," he said.

Palmieri, who stressed that he was stating his opinion and not official administration policy, said he thought the "only manageable solution" would be to create "a framework in which these people can live here legitimately, with some access to basic life-suport benefits -- things like food stamps -- but not enought to disrupt the government's spending capacity."

He said it was this consideration -- the potential drain on the country's financial resources in a recession -- that had caused the administration to reverse past U.S. policy of welcoming Cuban refugees in almost unlimited numbers and trying instead to stem the sealift.

The impromptu flotilla of small vessels making the 180-mile round trip between Key West and the Cuban port of Mariel has brought in almost 10,000 refugees in little more than a week. Palmieri conceded candidly that the administration's efforts to choke off the flow -- primarily by assessing fines against boat owners and appealing to the Miami Cuban community to stop financing the sealift -- so far have not been very successful.

For the moment, he said, the administration has no choice other than to stall. "Right now," he noted, "we're in a situation where we can't let them in and can't stop them from coming in, contradictory as it may sound."

To allow the wave of illegal immigrants to continue unchecked, Palmieri said, would strain the ability of southern Florida, and other areas to which the immigrants might disperse, to pay for their immediate needs and to provide jobs and housing.

He pointed out that these pressures, particulary in a time of recession, lash of domestic resentment, especially from blacks and others in low-paying jobs who would feel threatened by the newcomers.

"We're heading for a long, hot summer," he warned, "and if the numbers get really high, there could be a reaction reminiscent of what happened in the city ghettos in the 1960s.

On the other side of the problem, Palmieri continued, any move to prevent Cubans from coming in or send-budgetary belt-tightening and rising unemployment, could trigger a backing ships to impede the sealift would have an impact on Florida's vehemently anti-Castro Cuban community that "could push it into widespread civil disorder and even armed insurrection."

Over the next two or three weeks, he explained, the emphasis will be on trying to negotiate with the Florida Cuban community in order to cool the passions there and win understanding for a modified inflow that will allow entry to those with relatives in the rid of malcontents, to behave more responsibly and cooperate with an international approach to solving the refu [TEXT OMMITTED FROM SOURCE] United States and other special cases but not to everyone who wants to come.

Parallel with that, he said, the United States is exploring with friendly Latin American governments possible ways of pressuring Cuban [TEXT OMITTED FROM SOURCE]gee problem on the island.

While these efforts are under way, President Fidel Castro, who has encouraged the mass migration to get Palmieri said, the United States will continue to take in refugees and have the Coast Guard and Navy assist boats in the sealift that encounter trouble navigating the Florida Straits.

But, he admitted, while the influx can, be accommodated for another two to four weeks at its present rate, there eventually will come to a point -- probably in the 25,000 range -- where the administration will have to reasess whether the tide is slowing and,if not, consider sterner measures.

Thus in playing for time, the administration plans to work with private resettlement agencies to divert from south Florida those Cubans who don't have close family ties in the area. Palmieri noted there are a half dozen other communities in the United States that already have absorbed sizable groups of Cuban refugees.

There's a possibility that some of the thousands of Haitians in south Florida also will be processed through Eglin Air Force Base in the state's western panhandle.

Palmieri made it clear that he considers the Haitians and the Cubans in the same category and thus entitled to the same treatment, something lawyers for the Haitians claim has not been true the past several years.

Though both groups are now being given applications seeking asylum, which are supposed to be handled on a case-by-case basis, Palmieri said this isn't likely to happen. "That would take years," he said.

But Palmieri said he doubted all the applicants would meet the test for gaining asylum -- proving they have a well-founded fear of persecution if returned to their homeland -- so another solution is required.

That's what led Palmieri to outline his ideas about "a new framework" that would see Congress considering legislation to give all "undocumented workers" a chance for employment and permanent residence, with limited benefits.

"This would give the country the benefit of a work force that has found a place in the economy, without providing benefits that would invite even greater numbers," he said.

A White House official who has been involved in the administration discussion of how to handle the Cubans said special legislation to deal with the Cubans and Haitians is being considered. But extending some new category of treatment to Mexicans and other groups as well hasn't been talked about, he said.

When the Carter administration came into office in 1977, the Justice Department presented an elaborate package of legislation for dealing with the illegal Mexican alien problem.

But Sen. James O. Eastland (D-Miss.), who represented an area that used migrant workers, refused to let his Senate Judiciary Committee consider the matter.

By last year, when Sen. Edward M. Kennedy (D-Mass.) took over the chairmanship of the committee, both he and Carter administration officials viewed the proposals as a no-win issue in the politically important Hispanic community.

They agreed to shelve the legislation and set up a Select Commission on Immigration and Refugee Policy to study the problem.