A monthslong US manufacturing slump lessened last month, according to better-than-expected survey data published Friday, as demand showed signs of improving.

The Institute for Supply Management's (ISM) manufacturing index was 49.3 percent last month, up 0.9 percentage points from November, it said in a statement.

The figure was above market expectations of 48.5 percent, according to Briefing.com, but still below the 50-point mark separating expansion from contraction.

"US manufacturing activity contracted again in December, but at a slower rate compared to November," ISM survey chair Timothy Fiore said in a statement.

"Demand showed signs of improving, while output stabilized and inputs stayed accommodative," he added.

December marked the ninth consecutive month of contraction in the sector, which has been squeezed by the impact of higher interest rates on demand.

Seven manufacturing industries reported growth last month -- including electrical equipment -- while seven others contracted, according to the survey.

However, none of the six biggest manufacturing industries registered growth, Fiore said.

He added that "de-staffing" had continued last month, but should end soon, and that price growth had been "marginal."