The ISM manufacturing index rose to 53.8 from 51.4 percent in May, the organization said in its report, seen as a reliable gauge of US manufacturing.

Readings above 50 indicate expansion, so the report suggests a stronger pace of growth after six months of deceleration.

Private economists had on average expected a figure of 51.5 percent.

Survey chief Norbert Ore noted that the survey showed expansion in manufacturing for the 25th straight month, and represented an encouraging trend.

"The improved rate of growth in new orders is quite encouraging, particularly when combined with a slower rate at which prices are escalating," he said.

"These are the most positive signs that we have seen in several months, and they indicate that we may be through the 'soft patch' that many observers touted. High energy costs and the stronger dollar are still major concerns to purchasers."

Among the components of the main index, the ISM said production accelerated to a pace of 55.6 percent, while the employment index dipped to 49.9 percent, indicating a small contraction. The price index dipped to 50.5 percent, showing a smaller rate of increase.

Some said the ISM index contradicts other evidence that suggests economic slowing.