The Carter administration wants Congress to approve production funds for a new, neutron "killer" warhead even before the President decides if he wants to go ahead with it.

The 56-mile-range Lance missile warhead, nicknamed the "cookie cutter" by its designers, is the first publicly acknowledged tactical nuclear weapon designed specifically to kill people by radiation rather than destroy installations and equipment by heat and blast.

Money for the warhead -- said to be $10 million to $20 million -- is contained in the Energy Research and Development Administration's fiscal 1978 budget now before Congress.

The decision to build the warhead was made last year by the Ford administration. Neither President Carter nor Defense Secretary Harold Brown knew that money for its production was in the fiscal 1978 budget they had reviewed until news reports appeared two weeks ago.

Although the idea of a neutron bomb has been discussed by scientists for many years, never before has a decision been made to produce a version for use on the battlefield.

In a letter received yesterday by Sen. Mark O. Hatfield (R-Ore.), Dr. Joseph Perry, director of defense research and engineering in the Defense Department, said the President would make his decision on whether to go ahead with the enhanced radiation neutron warhead prior to the start of fiscal 1978, which begins Oct. 1, 1977.

"To afford maximum flexibility, particularly if he chooses" to go ahead with production, Perry asked Hatfield not to cut the warhead funds for the ERDA bill. Hatfield has introduced such an amendment in the Senate Appropriations Committee.

Perry's letter came in response to a Hatfield letter to the President asking his position on the amendment.

Yesterday, Hatfield said he intends to press his amendment when the committee takes up the ERDA money bill.

"This is backwards," the Oregon senator said in reference to Perry's letter. "We're supposed to respond to the President's request for funds. Here the President wants us to give him the money, then he'll decide if he wants to use it."

The first public description of the new Lance warhead came when declassified testimony before a House Appropriations subcommittee was released. In it, Alfred D. Starbird, ERDA's assistant administrator for national security, cryptically described the qualities.

Earlier last month, the Senate had approved ERDA's military applications authorization, but only one line in the Armed Services Committee report on the measure made mention of the warhead. It contained only the name, and the committee's decision to delete $3.2 million of the larger total amount being requested for production. It did not describe the type of weapon it was nor say that it was the first of its kind being produced for use against people."

According to weapons experts, the warhead would release large amounts of neutrons which in minutes would incapacitate and probably kill individuals in its target area.

If a normal nuclear weapon of the same kilotonnage were also dropped in the same location, blast or fire would destroy buildings far beyond the range of the killing neutrons.

Thus, experts say, military commanders and the President would hesitate to employ a regular nuclear weapon because of the widespread collateral damage it would wreak. The enhanced radiation weapon would be more credible for use because the building damage would be limited experts say.

The House is expected to take up later this week its version of the ERDA military applications authorization. Rep. Christopher Dodd (D-Conn.) is expected to raise questions about the neutron warhead.