A company owned in part by former Alexandria mayor Frank E. Mann agreed last week to pay more than $33,000 in real estate taxes and penalties it owes on valuable waterfront property.

The agreement came during a hearing on the tax issue before Circuit Court Judge Albert H. Grenadier. By agreeing to pay the taxes on the land, the firm may silence an issue that was raised during last spring's mayoral race, which Mann lost.

The land is owned by the Port of Alexandria company, owned by Mann, John C. Richards and Robert Sweeney. Mann and Richards previously have said they were refusing to pay taxes on the one-fifth of an acre because a federal claim against the City of Alexandria and six private landowners raised questions about the ownerhsip of the land.

The title claim, filed by the Interior Department in 1973 to prevent high-rise construction along the city's historic waterfront, remains unsettled. h

Recently, the City Council discussed the possibility of seizing the land owned by the three men and using it as part of the city's waterfront park system. One city official said if the taxes had been paid on the land, such an acton would not have been considered.

Although the taxes have been unpaid since 1974, Alexandria only began major efforts to collect delinquent taxes in the city about two years ago. Since then, the city has received $564,521.57 in delinquent taxes from property owners, according to a report presented to the City Council recently.

However, the city had been unsuccessful in collecting the back taxes, as well as interest and penalties, owed by the Port of Alexandria firm and took the case to court.

Last Friday, Nolan B. Dawkins, a city attorney, and attorney Yvonne Weight, representing the landowners, appeared before Judge Grenadier on a pre-trail motion by the city. During the hearing, Judge Grenadier remarked that the city's case appeared strong and urged both sides to settle, Dawkins said.

Faced with that, Weight agreed that the taxes would be paid, if it was understood that her clients might try to recover their money if the federal government wins its title claim.

Dawkins accepted that, and Grenadier then ordered an agreement be drawn up for both parties to sign. The total amount of money to be paid to the city is $33,900, Dawkins said.

Mann was defeated by Charles E. Beatley Jr. by a two-to-one margin in last May's election. Beatley's supporters charged during the campaign that it was inappropraite for Mann not to have paid "his" taxes. Although Mann is not listed in city land records as an owner of the property, he has acknowledged his ownership in the company.

The small piece of land, now occupied by a gunshop owned by Richards, may continue to be controversial in the coming months. Its current commercial use is incompatible with city and federal plans for the area, which call for open space on the site.