Stockpiles of imported iron ore at 25 major Chinese ports surged last week due to weak demand, new data showed on Tuesday.

At the end of the Feb 11 to Feb 17 period, inventories of imported iron ore stood at 99.93 million tons, up 8.18 percent from the previous week, according to a Xinhua-China Iron Ore Index report.

The index, compiled through research and analysis of 25 sea ports, showed that the price index for iron ore imports with a 62-percent purity grade dropped one point from the previous week to 122. The index for imports of 58-percent purity dropped two points to 110.

The report attributed the surge in stockpiling mainly to continued weak market demand after the Spring Festival holiday, which ran from Jan 31 to Feb 6.

Many factories in China stopped or slowed production as migrant workers returned home for the lunar new year.

The report said that steel companies still showed little willingness to increase iron ore purchases, so the imported iron ore market will still see weak demand in the coming week.