Two senior officials, in the administration's first extended comment on the recent demise of the "legislative veto," took pains yesterday to stress accommodation and cooperation with Congress in solicitous testimony before the House Foreign Affairs Committee.

In effect, the ranking deputies of the State and Justice departments told the committee that, despite the Supreme Court's decision on June 23 to strike down legislative vetoes, a move believed likely to trigger new battles between Congress and the executive branch, the Reagan administration is not looking for a fight.

"Little of practical significance need in fact change as a result of the Supreme Court decision," said Deputy Secretary of State Kenneth W. Dam. "If anything, I believe the decision will make the departments and agencies of the executive branch more, not less, conscious that they are accountable for their actions."

Legislative veto is a means by which Congress grants broad authority to the executive branch but reserves the right to reject or reverse particular uses of that authority. At least 16 major foreign policy laws, including those governing war powers, arms sales, foreign aid and the export of nuclear materials, contain some form of legislative veto.

Deputy Attorney General Edward C. Schmults testified yesterday that redrawing this legislation to constitutional specifications will not be as troublesome as some in Congress, including the House's chief counsel, have feared.

On the key legal issue of "severability," the question of what happens to the rest of a bill when its legislative veto provision is voided, Schmults said that the Justice Department will regard virtually every affected bill as valid minus its veto provisions.

"It's very heartening that you're not going to take, apparently, advantage of the decision," said committe Chairman Clement J. Zablocki (D-Wis.). "That is the greatest fear on the Hill."

Dam discussed four key foreign policy issues affected by the voiding of the legislative veto, each time concluding that Congress still has considerable review powers. The issues:

* War powers. Dam said that the administration still considers valid the requirements that the president consult Congress before sending troops abroad and that he report formally to Congress afterward.

Later, in an odd role-reversal in response to questions from Rep. Lawrence J. Smith (D-Fla.), Dam tried to convince skeptical committee members that Congress could force the president to withdraw troops by cutting off their appropriations. Smith said that there is enough money and material in the pipeline to support them for a long time.

* Arms sales. Dam said that the administration will continue to inform Congress of proposed arms sales to foreign nations. Rep. Stephen J. Solarz (D-N.Y.) said after the hearing that he will introduce legislation requiring that the president delay certain sales while Congress considers whether to pass a joint resolution that would permit them.

* Export of nuclear materials. Dam said that the strict standards limiting these exports and the requirement that the president notify Congress if he wishes to waive them remain valid.

* Trade status. Dam said that a similar standard-and-waiver procedure will continue to apply to decisions on most-favored-nation trading status for nations with questionable respect for human rights.

Four senators, meanwhile, introduced a bill yesterday to restore some of the review power Congress has lost with the voiding of the legislative veto.

Sens. Carl Levin (D-Mich.) and David L. Boren (D-Okla.), with two co-sponsors, are calling for a statute delaying the effectiveness of all new administrative regulations to give Congress time to "veto" them in advance by joint resolution. A joint resolution, which requires a majority vote of both houses, may in turn be vetoed by the president.