The Carter administration has decided to bypass the provisions of the 1980 Refugee Act and create a special category for dealing with the thousands of illegal Cuban and Haitian immigrants who have flooded into south Florida, officials said last night.

Victor Palmieri, the State Department's coordinator for refugee affairs, is expected to say in an official announcement this morning that the newcomers will be given "indefinite parole," allowing them to stay in the country for about a year. This will permit the administration to get past the November election before having to send legislation to Congress to clarify the refugees' legal status.

In addition, the new policy will provide benefits to be shared by federal, state and local governments, officials said. This will be about half as costly as the full federal reimbursement of local costs called for under the Rufugee Act.

The administration has been struggling with the politically sensitive issue referred to as "status and benefits" for more than a month. Officials acknowledge they have been searching for a way to provide equal treatment for the Cubans and Haitians without having it serve as a magnet for other Caribbean groups seeking a better life.

No clear consensus has developed in Congress. Sen. Edward M. Kennedy (D-Mass.), chairman of the Senate Judiciary Committee, wanted to use the emergency provisions of the new act. But several members of the House immigration subcommittee and many administration officials expressed concern that neither the Haitians nor Cubans met the definition of "refugee" in the law -- that they faced a well-founded fear of persecution if returned to their homelands.

Anxious members of Congress have tacked amendments on legislation in recent days to provide benefits for the newcomers. The supplemental fiscal 1980 appropriations bill in the House, for instance, was amended this week to provide $100 million for Cuban and Haitian resettlement.

More than 114,000 Cubans have arrived in the United States in an illegal boatlift since late April. Over the past several years, some 15,000 Haitians also have come here, according to the Immigration and Naturalization Service.

Supporters of the Haitians have charged that the Cubans were greeted with open arms by the administration while the Haitians were jailed, refused work permits and otherwise discriminated against.

The administration has pledged that the two groups would be treated equally. They all are being given 60-day paroles now and processed as applicants for "asylum." Asylum is supposed to be determined on a case-by-case basis, but officials agreed that it would take years and is thus impractical.

The use of "indefinite parole" is sure to be criticized in Congress because the new Refugee Act was passed, in part, since members were dissatisfied with the attorney general's use of parole in recent years to allow hundreds of thousands of Vietnamese and others into the country without limits.

Some administration officials have said they were concerned about submitting special legislation to Congress during an election year. But the president apparently is side-stepping the issue for now by using the indefinite parole.

Another key concern of the administration has been the cost of the program. A month ago the Office of Management and Budget told Congress it might cost as much as $300 million in fiscal 1980 to resettle the Cubans.

A supplemental request that went up to Capitol Hill this week, though, raised the estimate to $385 million just for immediate relocation costs, without addressing longer-range benefits such as Medicaid or welfare payments.

Officials have said the country cannot afford to take in an unlimited numbers of newcomers in this time of rising unemployment and attempted fiscal austerity. They estimated it could cost up to $2,000 per individual to give the Cubans and Haitians full "refugee" benefits, while paroling them initially would cost the government half as much.