Yields on short-term Treasury bills rose in yesterday's auction, as three-month bills hit their highest level since early August.

The Treasury Department sold $7.4 billion in three-month bills at an average discount rate of 7.24 percent, up from 7.21 percent last week. Another $7.4 billion in six-month bills was sold at an average discount rate of 7.26 percent, up from 7.23 percent last week.

The rates were the highest since three-month bills sold for 7.3 percent on Aug. 5 and six-month bills averaged 7.3 percent on Nov. 4.

The investment rates, which always are higher than the discount rates, were 7.48 percent on three-month bills at an average price of $9,817.00 per $10,000 face value, and 7.64 percent for six-month bills at an average price of $9,633.00.

Meanwhile, the dollar drifted down in New York yesterday on very little volume. Bank dealers said the market was awaiting this week's report on the gross national product and results of the $61 billion onslaught of Treasury offerings that began last Friday and will continue every day until Thanksgiving.