Chief Justice Warren E. Burger has backed away from urging Congress to construct a new office building on Capitol Hill immediately for the Administrative Office of the U.S. Courts.

In a June 10 letter to Sen. Robert T. Stafford (R-Vt.), chairman of the Senate Environment and Public Works Committee, Burger said that fully exploring the most cost-effective means of putting up the building would serve the taxpayers' interest.

"Please accept this letter as my assurance that I personally believe a slight delay now, justified by a sincere effort to hold costs to a lower level, is in the best interest of the public and therefore in the best interest of the judicial branch," Burger wrote.

The letter was sent after Sens. Stafford, Lloyd Bentsen (D-Tex.) and Daniel Patrick Moynihan (D-N.Y.) jointly told the chief justice that the fast-track approach to this construction project was unacceptable until the Senate could ensure that it was the most cost-effective means of providing offices for the workers.

Burger said that the three senators' recommendation "has great merit. Until June 7, I was unaware that there were any alternatives to construction under the supervision of the Architect of the Capitol."

The Administrative Office of the Courts is scattered over four downtown sites, and GSA had a plan pending before the House committee to relocate the agency to one building. GSA's plan involved acquiring new leased space totaling 172,572 square feet of office space for 741 employes at an annual cost of $5,177,160.

James E. Macklin, executive assistant director of the Administrative Office of the Courts, said the delay is likely to cause new hardships for his agency. "In what circumstance is it useful for managers to have to trot blocks to see their staff?" he asked.

Macklin said that the new delay in construction on Capitol Hill means that the General Services Administration will have to continue leasing space for the agency.

"As far as I'm concerned, the Administrative Office of the Courts still needs to be consolidated, it needs to be done soon, and it would be helpful for Congress to approve that while discussing long-range construction plans," Macklin said.

The committee is considering a mid-July hearing to explore options, including going ahead with a consolidation of the Administrative Office of the Courts downtown under a federal lease, constructing the new building under supervision of the architect of the Capitol, using a private developer to build the facility for the architect and exercising an option in a federal law that would allow the Union Station Redevelopment Corp. to construct the building.

The latter option had stalled after it appeared that the Reagan administration would not allow Transportation Secretary Elizabeth Hanford Dole to draw up the necessary papers to give the Redevelopment Corp. the right to borrow the property for the construction. DOT officials are reassessing their position, and the Senate committee is pressing for that option to be exercised -- clearing the question of who should build on the property.

Burger had been working behind the scenes with the architect of the Capitol, George M. White, to lobby the House to fund the proposed $70 million project. Last month, the House Public Works and Transportation Committee and its subcommittee on public buildings and grounds passed legislation authorizing the architect to plan for the construction. But when Stafford learned of the legislation, he ordered the project put on hold until staffers could conduct a full investigation to determine if the architect's pricing was reasonable.

Elliott Carroll, executive assistant to the architect, said the plans are on hold.

The architect's solution involved constructing a new building just east of Union Station that would cover 460,000 square feet of space and have about two-thirds of that space for office use. Underground parking would be included. Currently, Senate staffers park their cars on the property.

James G. Whitlock, GSA's regional public buildings commissioner, said GSA would not mind having the courts office moved to the grounds of the U.S. Capitol, because that would relieve the agency of the burden of having to find new leased space for the employes.