* Voestalpine says up to 3 pct of group sales affected
* Thyssenkrupp supplies 400,000-500,000 tonnes/year to U.S.
* Voestalpine shares down 1.6 pct, Thyssenkrupp up 0.8 pct (Recasts with German steel association, Thyssenkrupp)
ZURICH/FRANKFURT, March 9 (Reuters) - New U.S. tariffs on steel and aluminium imports will have a limited impact on two of Europe's top steelmakers, the companies said on Friday, while some shares slipped on the move to limit access to the world's second-largest steel market.
U.S. President Donald Trump slapped import tariffs of 25 percent on steel and 10 percent on aluminium on Thursday, exempting Canada and Mexico and offering the possibility of excluding other allies.
The European Union as a whole is the biggest exporter of steel to the United States, accounting for a fifth, or $6.8 billion, of U.S. steel imports, last year, according to figures from the German statistics office.
Shares in Salzgitter, Germany's second-largest steelmaker, were down 2.3 percent. The group did not respond to requests for comments, but its CEO said on Thursday that markets were overestimating the impact of the tariffs on its business.
Other European steelmakers include ArcelorMittal, the continent's biggest, whose shares were down 1.1 percent, while India's Tata Steel were down 5 percent. The U.S. represents around 10 percent of Tata Steel Europe's sales, an industry source told Reuters.
"The extent to which other sales are affected by import restrictions is being thoroughly examined," Austrian steelmaker Voestalpine said in a statement.
Responding to the tariffs, Germany's steel association called on the European Union to come up with effective countermeasures, warning Europe might be forced to absorb more volumes as a result.
"A maximum of about 3 percent of current Voestalpine group sales can be affected by the U.S. tariffs and the economic risk remains very manageable even in extreme cases," Voestalpine said.
Meanwhile, Thyssenkrupp, Germany's largest steelmaker, said it only supplied about 400,000-500,000 tonnes of steel a year to the U.S. market, or between 3.3-4.5 percent of total deliveries.
Shares in Voestalpine were down 1.6 percent at 0959 GMT, while those of Thyssenkrupp were up 0.8 percent.
German steel trader Kloeckner & Co could be one beneficiary of tighter supply in the United States, its Chief Executive Gisbert Ruehl said last week, pointing to the expectation that prices there could rise.
Ruehl said his company received all its steel in the United States from local manufacturers, adding Kloeckner & Co was therefore not affected by the tariffs. (Reporting by Michael Shields, Christoph Steitz, Tom Kaeckenhoff and Maytaal Angel; Editing by Adrian Croft/Douglas Busvine/Alexander Smith)