Federal construction money for the Washington Metro is being withheld from the Department of Transportation budget for fiscal year 1979 until local officials have completed their restudy of the subway.

Transportation Secretary Brock Adams, in briefing reporters on his new budget, said that "we expect (Metro construction money) will be a supplemental account."

Money for Metro construction becomes available as area localities eliminate once-planned interstate highways from their road networks. Then, the money must be reappropriated under an "interstate transfer" account before it can be spent for Metro. Almost $900 million in Metro construction has been scheduled with such funds.

Adams' budget also has no money for a greater federal share of the interest on the Metro revenue bonds. The original Metro financing package included a U.S. payment of 25 percent of the bond interest every year, and that, in the amount of $19 million, is included.

Since the construction began and it became obvious that the rest of the interest would not be available from fares, local officials have campaigned for the federal government to pick up some or all of the rest of the interest. This year, Congress appropriated 80 percent of the rest in a supplemental bill after heavy lobbying by Metro General Manager Theodore Lutz.

Local jurisdictions are scheduled to complete their restudy of the system and assemble a financial plan to build and operate it by Aug. 31. "I would like to see it earlier," Adams said, "and we'll do everything we can to cooperate."