The House, nearing completion of a $283 billion defense bill, yesterday reduced spending authorization for the Strategic Defense Initiative to the lowest level since the program's first year.

On a 225 to 189 vote, the House cut the space-based missile defense system to $2.3 billion for the fiscal year that begins next month, a figure $600 million less than was approved by the House Armed Services Committee and $2.4 billion below the Bush administration request.

The House action is expected to lead to a final SDI spending program of about $3 billion, once negotiations are completed with the Senate, which earlier agreed to spend about $3.7 billion next year. That would be a reduction of about $800 million from current authorized spending levels and about $1 billion below the high-water mark for the program two years ago.

Yesterday's vote reflected growing congressional skepticism about the need for a missile defense system in an era when the Soviet nuclear threat is diminishing. It was also a rejection of arguments by Republican lawmakers that the United States must continue to develop SDI to guard against an expected proliferation of strategic missile systems by nations such as Iraq.

Rep. Jon L. Kyl (R-Ariz.), seeking to increase SDI funding to about $3.6 billion, warned that continued cuts would lead to the nation "being held hostage by some tinhorn dictator."

The House rejected Kyl's amendment 273 to 141, and also killed on a 286 to 135 vote a move that would have reduced SDI to a $1.5 billion research program.

SDI proponents gained some strength this year because of the threat posed by Iraqi President Saddam Hussein and because of the U.S. troop deployment in the Mideast, but most lawmakers sided with Rep. Timothy J. Penny (D-Minn.) in holding that the nation needs a "defense policy that reflects the post Cold War-era."

In another indication of how the thawing of the Cold War has changed congressional views, the House yesterday made no attempt to revive the B-2 "stealth" bomber program.

The defense bill -- expected to win final House approval today -- would terminate production of the B-2 after 15 planes rather than build the 75-plane fleet sought by the White House.

The House also killed 216 to 200 an amendment that would have allowed members of the armed services and their dependents to undergo abortions at U.S. military hospitals overseas, at their expense.

Supporters had argued that the high cost of abortions at private facilities overseas was an unreasonable financial burden.

The Senate version of the measure, adopted last month, sets fiscal 1991 spending at $289 billion.