Saying it would open home ownership to more Americans, a coalition of mortgage bankers, builders and Realtors supports an administration proposal to raise the ceiling on federally insured home loans to $227,150.

Fannie Mae and a group representing smaller banks oppose the move, which would increase the ceiling for loans insured by the Federal Housing Administration by as much as $140,833 from current levels.The change, included in President Clinton's recent budget proposal to Congress, would raise the FHA-insured ceiling to the level of Fannie Mae and Freddie Mac, government-chartered mortgage market companies that function like commercial corporations and are publicly traded. Those companies would be competing more closely with the federal agency, which is part of the Department of Housing and Urban Development.

"We believe there is no single action Congress could take that would have a greater positive impact on increasing the opportunities for homeownership for Amer-icans," Marc Smith, president of the Mortgage Bankers Association, said.

He estimated the increase would allow some 300,000 Americans to become homeowners.

Smith was joined by David Seiders, chief economist of the National Association of Home Builders, and Layne Morrill, president of the National Association of Realtors.

They said a higher ceiling would not change requirements for potential home buyers for qualifying for mortgages.

The new nationwide $227,150 ceiling would replace the current system of 250 local limits, ranging from $86,317 to $170,362, based on prevailing home prices in different regions.

In a recent letter to Clinton, the head of America's Community Bankers, which represents 2,000 savings and loans and community financial institutions, said his group is "deeply concerned" about the administration proposal.

Raising the FHA ceiling would be inconsistent with the FHA's traditional goal of helping low-income borrowers buy homes, said Paul A. Schosberg. At the higher level, he added, a typical borrower would need to earn at least $80,000 a year to qualify.

The increase would provide "an improper subsidy to higher-income borrowers" and is a "disturbing misallocation of resources," Schosberg wrote Clinton.

David Jeffers, vice president for corporate relations at Fannie Mae, said the proposal would put the government into a new market for larger mortgages with which it has little experience.

"It's a serious set of public policy questions," Jeffers said in a telephone interview. Since the FHA's core business is helping families most in need, he said, the agency's move into a new market could have an adverse effect on poorer neighborhoods.