The freeze that virtually stopped all residential mortgage lending in the District of Columbia for more than two weeks began to thaw yesterday, as some of the city's largest suppliers of mortgage funds announced that they are back in business in the city.

The Federal National Mortgage Association (Fannie Mae) and the Federal Home Loan Mortgage Corp. (Freddie Mac), as well as the city's largest savings and loan, said yesterday that they again are providing money for mortgage loans in the city.

"We are eagerly looking forward to D.C. mortgages," said Don Hill, a spokesman for Freddie Mac. Hill said his agency had refused to accept more than $4 million in mortgages from lending institutions in the last two weeks. Those institutions now are free to submit new requests for the money, he said.

Together, Freddie Mac and Fannie Mae are the single largest source of home mortgage money in the city.

During the first nine months of this year, the Federal Home Loan Mortgage Corp., a government agency, bought about $66 million worth of mortgages originated by the city's 16 savings and loan associations. The Federal National Mortgage Association, a private firm, purchased 370 conventional home mortgages valued at $18.4 million, mostly from mortgage banking companies.

Thomas Owen, president of Perpetual Federal Savings and Loan, the city's largest, said Perpetual began to make loans again yesterday morning after backing out of the picture when Fannie Mae disclosed it had stopped funding D.C. mortgages on Nov. 5.

"We're now open to everybody," said Owen. He added that Perpetual had been forced to delay about a dozen residential settlements in recent weeks. h

Spokesmen for the savings and loan and mortgage banking industries said the nearly $70 million in settlements that were delayed in recent weeks now can proceed.

Yesterday's announcements that mortgage money is available followed the signing on Tuesday afternoon by President Carter on legislation validating the District's permanent mortgage ceiling at 15 percent. That removed the legal cloud on the city's usury rate that had prompted Fannie Mae and Freddie Mac to stop funding D.C. mortgages.

Home buyers still aren't welcome at all lending institutions in the city. Bruce Bryan, a spokesman for the Metropolitan Washington Savings and Loan League, said that the number of savings and loans accepting applications is still "spotty" because of the tight money situation. Savings withdrawals have plagued the thrift institutions all year, he said.

Interviews with officials at half the city's 16 savings and loans confirmed that the picture is varied. For example, at National Permanent Federal, the city's second largest savings and loan, senior vice president M. Bradley Griggs said they still are "out of the market" because of limited funds and will not be accepting loan applications for at least another week.

Griggs said, however, that National Permanent is honoring commitments that were in question until the president signed the bill.

Five lending institutions still aren't accepting applications for new loans, but are proceeding with loan commitments already made or else making loans to their current savings and loan customers only, officials said.

Interest rates at various savings and loans seemed to hover around 14 percent yesterday -- up from 13 percent a few weeks ago. An $80,000, 30-year mortgage at 13 percent interest would cost, in principal and interest payments each month, $884.80. At 14 percent, the same loan costs $948.80.

The mortgage freeze in the city was prompted by a ruling last month by a D.C. Superior Court judge that the City Council had illegally used its emergency legislative powers to extend a ban on condominium conversions. The moratorium was permitted to stay in effect until the appeals court could rule on the matter.

The ruling didn't deal with mortgage interest rates. But Fannie Mae and Freddie Mac officials decided that the council's latest approval of mortgage interest rate legislation, which passed under emergency powers Oct. 5, might be similarly illegal.

The action by the two agencies was criticized by many lenders, but spokespersons for the two organizations said they felt they had no choice.

"We didn't like having to do what we did," said Beth Van Houten, director of public relations for Fannie Mae. "But we really felt there was no other course."

Van Houten said the agency continued to buy FHA and VA mortgages, as well as those that complied with existing permanent interest rates, but would not buy commitments that relied on the emergency legislation.

The City Council then immediatley passed a permanent bill setting a 15 percent ceiling -- up from the old 11 percent permanent limit -- and Congress quickly rushed through its approval last week.

The president's signing of the bill came none too soon for a group of home buyers in the Glover Park area of the city.

Indeed, George Gilbert, a legislative assistant on the Hill who was one of five tenants trying to buy their apartment building under severe time restrictions, said that he called the White House nearly every working hour over the last few days to determine when the president might sign the permanent mortgage interest ceiling legislation.

Consequently, at 2:30 Tuesday afternoon, tenant Penny Moser, who works for Life magazine, was in the White House press office waiting for the president's signature so she could dash the document to loan officials at American Federal Savings and Loan.

While others there were anxiously awaiting word on the Iranian crisis Moser noted, "I'm sure I was the only person in the press room waiting for a copy of the mortgage bill."