The man redeveloping a 2,100-unit apartment development for low and moderate-income renters in Alexandria said last night that unless the city grants him a building permit by Sept. 30 he will be forced to go ahead with high-rent apartments or expensive condominiums on the site.

The development, the decaying Shirley Duke-Regina apartment complex, was purchased by developer Morton Sarubin two years ago after its previous owners declared bankruptcy. It is almost totally vacant while being renovated: when reopened it will contain about 7 percent of the city's rapidly diminishing rental apartments.

Sarubin told City Council members last night that if he obtains a building permit by the end of the month to go ahead with renovation, he will be able to obtain a $53 million federal loan guarantee enabling him to set aside 423 units for subsidized renters and hold rents in the remaining 1,700 apartments to no more than $400 a month.

Sarubin said renovation is expected to take slightly longer than two years.

Under a plan the city approved last year, Sarubin was to set aside 423 units for low-income, subsidized renters.

After last night's meeting with the council, designed to clear up what Sarubin called misunderstandings, he told a reporter that if he fails to get the building permit and the loan guarantee, "simple economics" will force him to produce units renting for $500 to $800 a month or expensive condominium apartments.

He needs the building permit to make design changes he has planned for the buildings, but says he could go ahead with a more expensive project without the changes.

The permit has been held up because of a dispute among city officials over whether Sarubin needs to submit a complete site plan for the project.

The issue became more complex last week when several planning commissioners who saw site plans Sarubin submitted for some aspects of the project called them inadequate. That led some council members to voice apprehension that the complex, if developed according to plan, might soon deteriorate and become crime-ridden. Before the complex closed for renovation, Alexandria police maintained that it was a source of much crime in the city.

Sarubin denied to the council that such deterioration would be possible under his plans.

On Saturday, the council is scheduled to consider a resolution offered by council member Carlyle C. Ring (R) supporting the city staff demand for a complete site plan for the complex.

At its first regular meeting of its term of office, the newly elected council voted unanimously last night to seek new state laws to effectively control the 1,100 taxicabs licensed by the city. Members of the city staff said the cabs concentrate on serving National Airport, a federal enclave over which the city has no jurisdiction.

"I have great concern about the taxicab business in Alexandria" said Mayor Charles E. Beatley Jr., a Democrat. "They take their license and run. They don't answer calls. We get complaints about them. They don't serve the city. I think we should have an investigation of what should be done.We have a problem."

The council also scheduled a hearing for Saturday on a proposal to ban "instant bingo"-- a controversial form of bingo-- from the city.