A rebound in defense orders related to the Persian Gulf War helped push up new orders for long-lasting manufactured goods, such as cars, computers, missiles and machinery, by 4.4 percent last month, following a 10.1 percent plunge in November, the Commerce Department reported yesterday.

Large increases in defense orders for shipbuilding and private orders for commercial aircraft and parts more than offset a drop in orders for motor vehicles, as overall orders for transportation equipment rose 13.6 percent to $32 billion. Excluding the defense and aircraft industries, new orders fell 3.4 percent, the department said.

David Resler, senior vice president and chief economist for Nomura Securities International Inc. in New York, said December's gain "doesn't do much to restore orders to pre-November levels. ... I find lots of room for disappointment." Some sectors' orders are at their lowest levels in two to three years. "The economy is still in a recession and I see no signs of recovery in this report," he said.

Meanwhile, the Labor Department said its employment cost index, the nation's most highly regarded measure of changes in labor costs and a key measure of inflationary pressure, rose 0.9 percent in the October-December period and 4.9 percent in the past 12 months. In the year ended December 1989, the index rose 5 percent.

As has been the case for several years, the cost to employers of providing benefits, particularly health insurance, rose much more rapidly than wages and salaries. In the last three months, for instance, wages and salaries rose a seasonally adjusted 0.8 percent while the cost of benefits jumped 1.4 percent.