China's producer price index (PPI) contracted 2.3 percent year on year in March, following a 2-percent decline in February, data from the National Bureau of Statistics (NBS) showed on Friday.

The index, which measures inflation at wholesale level, has been in deflationary territory for 25 consecutive months, the longest drop since the 1990s.

Among the 30 main industries surveyed, 14 sectors including power generation and oil refining gained month on month, while 16 sectors including non-ferrous metal smelting and coal exploitation fell month on month, said Yu Qiumei, a senior statistician with the NBS.

Meanwhile, industries began to replenish stocks in March after the Spring Festival, China's Lunar New Year, which boosted price rebounds of some products like sulfuric acid, electrolytic copper and liquefied natural gas, Yu added.

The NBS said the consumer price index rose 2.4 percent year on year last month, gaining 0.4 percentage points from February.