Financially strapped homeowners facing foreclosure could get a reprieve under a long-awaited federal housing program that will make the payments on a borrower's FHA-insured mortgage for up to three years.

But critics charge that the relief the program promises may not be worth the wait. Some say that it's a worse deal for homeowners than an existing HUD mortgage relief program.

The Temporary Mortgage Assistance Payment plan could be launched as early as next April, according to Bill Glavin, a Department of Housing and Urban Development spokesman. The agency must complete a procedural handbook for HUD employes and select a contractor to handle the accounting. The plan calls for HUD to make part, or in some cases all, of a homeowner's mortgage payments for 18 months, with the department having the authority to continue payments for another 18 months if the borrower is still in need.

Congress has allocated $25 million for the program's first year. In addition, HUD has almost finished evaluating bids from prospective contractors, Glavin said.

Statistics compiled by the Mortgage Bankers Association of America, a trade group representing lenders, show that foreclosures in process increased from just under 1 percent of all FHA mortgages in the second quarter of 1985 to more than 1.5 percent during the same period in 1987. Of borrowers involved in the 64,000 foreclosures reported in fiscal year 1987, only 4,429 were accepted into the assignment program, the existing aid plan.

Several years of controversy have delayed the mortgage assistance plan, which was authorized by Congress in 1980.

A federal judge blocked HUD from beginning the program in 1982 because it did not offer the same foreclosure protection provided in the HUD assignment program, as required under an earlier out-of-court agreement settling a 1973 lawsuit. That case arose after lenders in Chicago quickly foreclosed on the loans of thousands of homeowners who had missed payments during a severe recession in the early 1970s, according to William P. Wilen, a lawyer for the Legal Assistance Foundation of Chicago, which filed the suit.

The new temporary mortgage aid plan could face still more legal problems. Wilen says his organization will challenge the program once more in court because it still does not offer the same level of protection as the assignment program.

He said that under the newer assistance plan, interest will continue to accrue on the money the borrower owes HUD throughout the life of the loan. By contrast, under the existing program, interest accrues only during the forbearance period.

"The interest stops accruing once the homeowner starts repaying the missed payments," Wilen said. That, he says, lessens the amount a borrower must pay back and boosts his or her prospects for repaying the money.

Under the older assignment program, HUD buys certain financially troubled homeowners' loans from lenders and then, as a borrower's new lender, either suspends or reduces payments for up to 36 months. The new payment plan calls for the borrower's current lender to keep the mortgage. Homeowners would pay HUD up to 35 percent of their net effective income and the agency would then pay the lender each month. Glavin said the department expects to save money because it will not have to pay off lenders to assist homeowners. He said the agency has not estimated the savings from the temporary mortgage assistance payment program.

As with the assignment program, borrowers would have to repay HUD for the assistance, which would become a second mortgage on a home. Homeowners would have up to 10 years to repay HUD, at either the original mortgage rate or the current market rate, whichever is lower.

The temporary mortgage assistance payment program would apply the same eligibility criteria as the older assignment program. To qualify for aid, homeowners would have to be three payments behind and facing foreclosure through no fault of their own. A borrower who has been laid off from a job, for example, would qualify for the plan. Borrowers must also have a "reasonable prospect" of resuming full mortgage payments and of repaying the assistance.

As in the assignment program, lenders could not foreclose on an FHA mortgage without first determining whether the delinquent borrower qualifies for mortgage assistance and recommending him or her for the aid if he or she is eligible. HUD has 90 days to make a final decision on the recommendation. Homeowners would have the right to appeal directly to HUD if lenders decide they don't qualify for assistance.

Russell Rothstein, a vice president of Investors Home Mortgage Corp. in Bethesda, said the program should "help save credit ratings and houses. Because once {a borrower} gets a foreclosure on the record, it's very hard to get another mortgage. It's one of the worst things to have. The first thing that lenders look at is your mortgage payment record."

The new program will save lenders money, said Tim Kalaris, a senior loan officer for Maryland Builders Mortgage Corp. in Silver Spring. "It costs about $2,500 to foreclose on a home. Ideally, the costs should be absorbed by the sale of a property. But in reality, you end up with a shortfall."

Moreover, the program should reduce the number of foreclosures, which in turn will help keep down premiums FHA borrowers must pay for insurance that pays off lenders in case of default. Such premiums run 3.8 percent of the mortgage, but increased costs due to foreclosures would put pressure on the government to raise the premiums. "Mortgage Insurance premiums have a direct relationship to foreclosure ratios. The more foreclosures, the higher the premiums will be," Kalaris said.

But Janet Frank, director of residential finance and government agency relations for the Mortgage Bankers Association, questioned whether the program will have that much impact. "The number of assignments is a small percentage of defaults. It is for the exception, for the person who may have lost his job because a plant closed down and is being retrained for another occupation. There are cases this program will save. But it's not intended to be for the majority of people who get into trouble."

Richard Tulloch, an agent with Pearl Properties Inc., a Silver Spring company that sells foreclosed properties, said it is unrealistic to expect that people who don't have enough money to pay the mortgage will be able to pay even higher rates once they begin to repay the assistance. "It's just stringing them along," he said.