The nation's merchandise trade deficit rose slightly to $3.58 billion in February as the benefits of a sharp drop in oil imports was more than offset by a worsened trade balance for manufactured goods, the Commerce Department reported yesterday.

The value of imported crude oil and refined products fell by 33 percent from the January level. Daily imports averaged 3.7 million barrels, down from January's 4.8 million, while the average price per barrel dropped from $31.92 to $30.49.

Oil imports fell so sharply in part because oil companies were drawing down their inventories rather than replenish them when a drop in world oil prices was expected. Imports have been even lower in March, but most analysts expect them to go back up now that OPEC has officially lowered its basic price from $34 to $29 a barrel.

The decline in oil purchases allowed the United States to run an overall surplus with the members of OPEC of $151 million.

But trade with Japan moved further into the red as the monthly deficit swelled from $1.331 billion in January to $2.219 billion in February. The next largest deficit was with Canada, $901 billion, down from $1.039 billion the month before.

By law, the merchandise trade balances are figured with exports being priced according to their value at the point of export. Imports, on the other hand, are priced including the cost of insurance and freight to the point of importation--which inflates the size of the trade deficit. The Commerce Department must wait 48 hours before it can release information showing exports and imports valued on the same basis.

Separately, the department reported that sales of new single-family houses fell 6 percent last month to a seasonally adjusted annual rate of 558,000. The rate nevertheless was 49 percent higher than in the same month a year earlier.

Dr. Jack Carson, chief economist of the National Association of Realtors, blamed bad weather for the failure of new home sales to continue the recent upward trend.

Sales are strong enough that "the shortage of new homes for sale actually is driving up home prices," Carlson said. "February's median new home price of $75,100 was 1.2 percent above January's median. This means that these prices are rising at an annual compound rate of 15 percent, very close to the 14 percent increase in new home prices during the last 12 months."