The Justice Department, in a revised title claim filed this week, is contending that the federal government owns more of the Alexandria waterfront than it has ever laid claim to before.

Justice Department attorney James T. Draude presented a list of boundaries to a federal magistrate in the District, outlining the government's expanded claim. The new boundaries were based on soil studies taken last summer in an effort to determine a 1791 high tide line, which the government contends marks the federal property line along the waterfront.

The new claim raised some questions as to whether a seven-year dispute between city and federal officials can continue on schedule.

"I am surprised at their finding," said Alexandria City Manager Douglas Harman. "It's difficult to see what the differences are between the new findings and the old ones. I don't know what effect this will have (on city-federal negotiations)."

"I'm confused," said city attorney Cyril D. Calley. "I wonder when we can try the original case, instead of dealing with these modifications."

The federal government originally sued the city and several private landowners in 1973, claiming title to the waterfront because of an obscure 1791 high tide mark. The 1791 line apparently has disappeared, as have original maps showing its location, although the line was thought to meander close to the water's edge.

Federal officials have said privately that the title suit was filed in order to protect the area from highrise development along the shore line, which federal planners say is national treasure. The 1973 suit has stopped virtually all development along the waterfront.

In the new claim, the federal government contends that the 1791 line follows a series of city streets in the Old Town area. The government is claiming title to land east of Union Street between Gibbon and Oronoco, and east of North Fairfax Street between Pendleton and Third Street.

The government also is claiming title to an adjacent area that includes, for the first time, all of the Marina Towers apartment complex near National Airport and the Pepco utility plant near Washington Boulevard.

However, attorney George H. Clark, who represents the owners of the Marina complex, voiced little concern about the newly defined claim.

"That was for technical reasons," he said. "It does not affect anything. We have intended all along to give the government a small strip of land . . . for use as a bike path. Anyone who's making a big deal out of the new claim is making much ado about nothing."

For several years, the city and federal governments have argued over what development is appropriate for the waterfront. Last year, in separate but similar plans, they agreed the best use of the 39-acre area would include parkland, open space and some height limitations.

City and federal attorneys will appear before federal magistrate Jean Dwyer on May 28 to see if Dwyer will accept the government's expanded claim. That is the same day the city and federal government will hold the first of several public hearings on the land dispute.