Mayor Marion Barry yesterday softened his plan to evict illegal public housing tenants, saying that residents will be allowed to add names to their leases and that his administration's estimate of 40,000 illegal public housing residents is about 36,000 too high.

But Barry's statement, designed to clarify the matter, came on a day when the issue of illegal tenants seemed more confused than ever.

On the one hand, Barry's office issued a statement, which was attributed to the housing director, saying that residents would have 60 days to comply with rules by adding the names of unauthorized residents to their leases.

On the other hand, the housing director already had sent out 4,000 notices telling the legal residents that all unauthorized persons in their units would have to be gone by June 30 or the legal residents would be evicted along with the illegal ones.

To complicate matters further, the U.S. marshal for the District said that regardless of the number of illegal residents, his office could not carry out public housing evictions because of a staffing shortage.

"I think the mayor and his administration have shot themselves in the foot on this one," said City Council member John Wilson (D-Ward 2), a member of the committee that oversees housing. "They are trying to get control of something that they have lost control of."

Many of the District's 11,679 public housing units have deteriorated, and the housing department has come under criticism for delays in making repairs and for having a high vacancy rate despite the 11,000 people on a public housing waiting list.

The government's effort to remove illegal residents was made public Monday when Barry issued a report on the condition of public housing. The report estimated that 40,000 persons are living in public housing illegally, and Barry said housing officials would move to "get everybody who is not on a lease out of the units" because they contribute to the wear and tear on units but do not pay rent.

But yesterday, the mayor questioned his administration's estimate of illegal residents, which had been based on information obtained during fire investigations.

"The 40,000 estimate is an outrageous number," Barry said through a spokesman. "It could not be that high. I don't know where they got that figure from."

Annette Samuels, the mayor's press secretary, said the mayor had seen a draft copy of the report, called "The Barry Administration Reports to the People on Public Housing," but did not read the final 73-page version that was handed to him before he released it at a Monday news conference.

"He admits that the figure looks foolish, and it is," Samuels said.

The statement released by Barry's office said "updated calculations" place the illegal public housing estimate at 3,000 to 4,000 people. In addition, the statement said that residents not listed on a lease could be added "as long as total family incomes do not exceed the limits" set by the U.S. Department of Housing and Urban Development. Eviction steps would be carried out only after a resident had failed to comply.

Although on Monday Barry said his administration did not plan to take any special steps to house persons who might be evicted, the statement issued yesterday said the housing department would provide housing assistance by referring people to the District's relocation services "regarding available housing on the open market."

Before those clarifications, Department of Housing and Community Development Director Madeline M. Petty on Tuesday mailed notices to 4,000 public housing residents -- senior citizens citywide and residents in family public housing complexes in Southeast -- warning that they must comply with their leases or be evicted.

"You have until June 30, 1986, to put your family in full compliance with your lease agreement, and all unauthorized persons living in your unit must be gone by this date," Petty wrote.

Petty indicated that the notice was part of a "spring offensive" that is "an all-out effort to evict" residents who are violating their leases. In addition to targeting illegal residents, the notice warned residents that the housing employes are documenting lease violations that include misrepresentations about family income, illegal activities, abuse of property and failure to pay rent.

"Should the department evict you and your family for failure to comply with your lease agreement," the letter to tenants said, "you will not be eligible for any city relocation assistance (i.e., furniture storage and/or temporary housing accommodations.)"

U.S. Marshal Herbert M. Rutherford III, whose office is responsible for carrying out court-ordered evictions, said the District government sent him a letter last week requesting a meeting to discuss evictions of public housing tenants. Rutherford said, however, that because of federal budget cuts, his office has reduced its daily evictions from 60 to 20 and has a backlog of 1,400 eviction orders. "I'm doing well to get those done," said Rutherford. "There is no way I can add any more at this time."

The eviction plan came under criticism from housing advocacy groups that maintain there is a shortage of affordable housing for low income residents. But yesterday, Kimi Gray, head of the public housing residents' advisory group, held a news conference to praise the mayor's plan to force compliance with lease agreements.

Gray said that public housing tenants have been asking the city since 1972 to enforce the leases and that Barry's action "is long overdue and is going to clean up public housing."