China is to impose tariffs of up to 55% on cold-rolled steel imports from five countries, which it says are hurting its domestic producers.
Steel has become an emotive international trade issue
The Ministry of Commerce in Beijing said that steel imports from Russia, South Korea, Ukraine, Kazakhstan and Taiwan were being sold below cost.
The move comes against a background of bitter global steel trade disputes.
China - which is experiencing an industrial boom - is the world's top steelmaker and user.
The BBC's Louisa Lim in Beijing says that with steel in everything from skyscrapers to cars, China is fuelling the world's steel industry.
But domestic steelmakers are facing stiff competition from cheaper imports as they struggle to update their own outdated technology, our correspondent adds.
The trade ministry in Beijing said in a statement on Wednesday that Chinese producers were being deliberately undercut by foreigners.
"The ministry has decided that dumping of such products does exist, and has caused substantial damage," it said.
The tariffs on cold steel rolls go into effect immediately and will remain in place for five years.
On the Chinese markets shares in local steelmakers surged following news of the latest tariffs.
Tit for tat
China's measures are however likely to fuel concern abroad.
The Chinese Government has poured money into the steel sector, sparking warnings that China's steel industry could pose a threat to other countries' steel sectors in the next 10 years.
In December US President George W Bush repealed US tariffs on imported steel to avoid a damaging trade war.
The move followed a World Trade Organization decision that the duties, imposed in March 2002, were illegal.
And less than three weeks ago China lifted its own tariffs on American steel imports - they had been imposed after the US tariff decision a year earlier.