The District of Columbia Zoning Commission voted yesterday to approve an increase in building heights along a five-block section of Pennsylvania Avenue to allow the construction of 16-story buildings.

Its action was the next-to-final and probably decisive step in raising the current building height limitation of 13 stores. The decision must be reviewed by the National Capital Planning Commission, which is believed to support the proposal but, in any event, has no power to block it.

The commission's decision, reached by a 3-to-0 vote, applies to the north side of Pennsylvania Avenue between 10th and 15th streets NW - a stretch bracketed on the east by the J.Edgar Hoover FBI Building and on the west by the U.S. Treasury.

The height increase was requested jointly last October by the D.C. Municipal Planning Office and Pennsylvania Avenue Development Corporation, the federal body that is sponsoring the redevelopment of the nation's most ceremonial boulevard. The proposal won near-unanimous support at Zoning Commission hearings in February.

Probably the first beneficiaries of the new rules would the National Press Club and the John C. Portman Jr. interests, of Atlanta, which have announced plans to build a $100-million hotel, office and shopping complex on the block now occupied by the National Press Building.

That building is at 14th and F streets NW, one block north and uphill from Pennsylvania Avenue. The south side of the block faces Pennsylvania Avenue.

At the commission hearing, Henry Keys, speaking for the National Press Building Corp., said the three additional stories "represents the difference between a profitable and a losing proposition."

Building heights in Washington are limited by a law passed by Congress in 1910, chiefly as a fire safety measure but also intended to prevent the erection of skyscrapers what would overshadow the Capitol dome.

Under the 1910 law, the maximum height in most of the city is 130 feet. A special provision in that law permits buildings up to 160 feet, or 16 stories, along Pennsylvania Avenue.

The city, in adopting its own zoning rules in the 1920s, did not take advantage of the 160-foot provision. Yesterday's vote reversed that decision.

Three buildings clustered around 14th and Pennsylvania - the Munsey Building, the National Press Building and the Willard Hotel - already exceed the current height limits. But they either were built before the enactment of the 1910 law or were granted special exceptions to raise to 155 or 160 feet.

In taking yesterday's vote, commission members Walter Lewis, George White and JOhn Parsons stressed that the easing of the height limit on Pennsylvania Avenue does not set a precedent for allowing higher buildings elsewhere in the city.

Mayor Walter E. Washington has proposed allowing 160-foot buildings at a few selected locations in the older part of downtown Washington north of Pennsylvania Avenue. His proposal is pending before the House District Committee, and is not affectd by yesterday's Zoning Commission vote.