Global steel prices have slumped as Chinese producers, which account for about half of worldwide steel supply, have flooded export markets, bringing protests and anti-dumping complaints by the United States and the European Union among others.

In November, the U.S. Commerce Department said in a preliminary finding that nine exporters, including Germany and four other EU member states, had dumped certain imports of carbon and alloy steel cut-to-length (CTL) plate. German steel producers were assigned dumping margin of 6.56 percent by the U.S. Commerce Department while companies from other countries face anti-dumping duties of up to 130.63 percent.

Among the German companies accused of dumping were Dillinger Huette [AGD.UL] and Salzgitter.

The November preliminary report has been criticised for appearing to use alternative methods for calculating dumping margins, which breaks World Trade Organization (WTO) rules.

Germany's Foreign Minister Sigmar Gabriel is worried the report, which is expected to be finished soon, will be used by U.S. President Donald Trump's administration to disrupt international trade.

"It is to be feared that ... the new U.S. government might be prepared to allow U.S. firms to conduct unfair dumping competition, even if this violates international law," Gabriel said on Friday.

"We Europeans must not accept this," Gabriel said, adding that he underlined his concerns in a letter to European Union trade commissioner Cecilia Malmstrom and urged her to take a firm stance in talks with U.S. counterparts on the matter.

The European Commission, the EU's executive arm, is in charge of trade matters in the 28-member bloc.

Gabriel said both Europe and Germany wanted the U.S. to stick to established WTO rules when calculating dumping margins, adding companies could have a disadvantage when other calculation methods were applied.

He said German officials had contacted U.S. counterparts on various levels to insist that "established, fair rules" had to be applied in the case.

The dumping case is likely to be the first to be concluded in the steel sector under Trump who has said he will bring back manufacturing jobs by putting "America first" and punishing imports through a border tax.

(Reporting by Michael Nienaber,; Editing by Vin Shahrestani)