Expansion in China's manufacturing activity gained momentum in February as producers revved up output to meet an increase in new orders that were mainly bolstered by rapidly growing foreign demand, an industry survey sponsored by Caixin showed Wednesday.

The Caixin China General Manufacturing Purchasing Managers' Index (PMI) rose to 51.7 last month from 51.0 in January. The February reading tied with that recorded in July 2014 as the second-strongest in more than four years.

The official manufacturing PMI came in at 51.6 percent in February, 0.3 percentage points higher than that recorded in January, according to data released Wednesday by the National Bureau of Statistics.

The Caixin survey is based on data provided by more than 500 factories and mines across the country. A reading above 50 indicates expansion, while anything below that points to contraction.

The survey showed total new orders continued to increase last month, with export businesses increasing last month at their fastest rate since September 2014, leading to a further upturn in output and manufacturers' purchasing activities, which edged up to their strongest in over two and half years.

The cost of raw materials rose sharply in February, and firms raised output charges to protect their profit margins.

The Chinese economy came off a strong start this year, with key economic indicators, including those for trade and inflation, all rebounding.