The decision follows a symposium called by the National Development and Reform Commission (NDRC), the market regulator, ports association and some port firms, according to an NDRC statement.
"The meeting studied measures including greatly shortening the free storage period for iron-ore traders, raising costs of portside hoarding, and preventing excessive hoarding," said the statement.
China's state planner has issued six statements since late January targeting fast-rising prices of the steelmaking ingredient, urging information providers to ensure the accuracy of published data and trading firms to release high stockpiles.
The most-traded iron ore futures on the Dalian Commodity Exchange, for May delivery, had tumbled more than 15% since the first NDRC notice and been volatile in the past week. They closed down 0.8% on Wednesday to 700 yuan ($110.65) per tonne.
