A booming local economy has led District of Columbia finance officials to increase their official forecast of city tax revenues in fiscal 1979 by $45.4 million.

When the city presented its proposed 1979 budget to Congress, itestimated that local taxes - on income, sales, real estate and a variety of other sources - would bring in $929.5 million in the 12-month period starting next Oct. 1.

Now the Department of Finance and Revenue has raised that figure by a shade under 5 percent, to a predicted tax income of $974.9 million.

Kenneth Back, the city's director of Finance and Revenue, said the new forecast "represents the booming economy in D.C.," which is pushing sales, profits and personal incomes upward.

Among the newly projected increases are these:

Sales and use taxes, estimated earlier to yield $153 million, are now expected to bring in $165.1 million. This is partly the result of a building boom, since taxes are paid on building materials. Back said, however, that retail sales tax collections are now running 20 percent ahead of last year.

Individual income taxes, previously estimated at $214.8 million, are expected to yield $224 million. Back said this represents more people working, and at increased salaries that push them into higher brackets.

Corporate income taxes, which were expected to bring in $39.3 million, now should yield $46.6 million.

Unincorporated business taxes, previously estimated at $17.2 million, should go up to $18.6 million.

Among the city's major tax sources, only the levy on real estate - which is providing about 22 percent of the city's locally raised revenue this year - is not expected to grow.

The D.C. City Council is scheduled to vote final enactment today of a real estate tax reform package that would, in one pending version, reduce collections from homeowners next year by $13.9 million. This may be offset partly by new construction and taxes on business property.

For business taxpayers, the increased tax yield may prove to be a mixed blessing. In the past, Congress has used increased local tax collections as a reason for holding down or even cutting the federal payment to the city, which represents the U.S. government share of municipal operating costs.

The subcommittee on D.C. Appropriations was aware of the new higher tax estimates, a committee aide said yesterday, when it voted recently to recommend a cut in the federal payment $12 below the current fiscal year's level of $276 million. President Carter is supporting a federal payment of $317 million.

The full House Appropriations Committee will consider the level of the federal payment Thursday when it acts on the city's proposed $1.3 billion operating budget for fiscal 1979.

The increased revenue forecast was disclosed yesterday by Marion Barry, chairman of the city council's Committee on Finance and Revenue. REVENUE, From B1>

He said at a news conference that the increase "gives us all the more reason to move ahead with the property tax relief" proposed in different versions by himself and by Mayor Walter E. Washington, against whom Barry is running.

Barry (D-At Large) said he will urge the council to reverse a vote it took June 27, when it accepted an amendment offered by David A. Clarke (D-Ward 1) to assess large apartment houses as residential rather than as business property.

Barry released a city estimate that Clarke's amendment would reduce real estate tax collections by $7.8 million, in addition to the $13.9 million in the basic tax reform package. The department also said Clarke's amendment poses difficult administrative problems.

Clarke said he hopes to persuade the council to raise taxes on business properties to make up the potential $7.8 million loss from apartment house taxation.