Plans to build two huge federal offices that would house up to 25,000 workers in the Washington suburbs have been halted at least temporarily in Congress, caught in a political crossfire between a senior senator and the Bush administration.

Sen. Daniel Patrick Moynihan (D-N.Y.) has moved to block construction of new offices for about 20,000 Navy employees in Northern Virginia and almost 5,000 Internal Revenue Service workers in Prince George's County. The projects would cost an estimated

$1 billion, and have been touted by lawmakers from Maryland and Virginia as economic boons for their states.

Moynihan, chairman of a Senate Environment and Public Works subcommittee that has jurisdiction over the projects, refused to authorize construction of the buildings at a committee meeting this week.

A Moynihan spokesman, Brian Connolly, said yesterday that Moynihan will not clear the way for work to begin until the Bush administration determines how the government will pay for these and several other federal buildings.

Moynihan "has no objections to these two particular projects," Connolly said, but that "the senator believes there is no need in proceeding further . . . until there is a clear decision on how these buildings will be financed."

He said that in the past two years, Congress has authorized construction of 13 federal buildings, "and none has been built."

The Bush administration wants to avoid borrowing money to build several major federal facilities, and sent legislation to Congress this week that would provide almost $1 billion in the 1991 budget for the Navy and IRS buildings. Moynihan, however, says pending budget cuts make such a large expenditure unlikely and wants to stretch out payments over 20 or 30 years.

Lawmakers from Maryland and Virginia predicted yesterday they would be able to salvage the projects, but there were signs that federal money woes are likely to shrink the Navy facility. Under current plans, the Navy would consolidate workers scattered throughout many offices into a 3 million-square-foot building at a cost of almost $800 million.

Two Virginia Republicans, Sen. John W. Warner and Rep. Frank R. Wolf, said yesterday they are asking the Navy to reevaluate its proposal and see if it can make do with less space and less money.

"The original concept of this building was based on a 600-ship Navy, and that has now been revised" downward, Warner said. "In my judgment, {Navy officials} have to make more realistic plans."

The IRS facility in Prince George's would consolidate workers from more than 20 locations into a 1.2-million-square-foot office at a cost of more than $200 million. There were no indications yesterday that the size of that project is being reconsidered. Charles Siegel, a spokesman for Rep. Steny H. Hoyer (D-Md.), said "we intend to be working with Sen. Moynihan to resolve the problems he has."

The Navy and IRS projects are already years behind schedule, in part because of previous political conflicts. When the Navy intially proposed building a new facility in Virginia, Hoyer inaugurated a tug-of-war with Wolf in an attempt to relocate the facility to his district in Prince George's.

The two settled the issue last fall with a deal that allowed the Navy to remain near the Pentagon in Virginia, but moved some IRS employees out of the District into Prince George's. Both sides said yesterday that agreement remains in place.

But Connolly, Moynihan's spokesman, said yesterday that the Bush administration "has created tremendous uncertainty on the Hill about how they plan to proceed" with financing for federal construction, creating a backlog of unbuilt buildings throughout the Washington area.