Citing concerns about national security, Trump on Thursday launched a trade probe against China and other exporters of cheap steel into the U.S. market, raising the possibility of new tariffs.
In Japan, shares in Nippon Steel (>> Nippon Steel & Sumitomo Metal Corp) rose 1.3 percent, after five weeks of steady losses, partly on speculation that any action by the U.S. would mostly target China which is easily the world's largest producer.
South Korean steelmaker Posco (>> POSCO) followed with gains of over 2 percent, while Taiwan's China Steel (>> China Steel Corporation) advanced 1.3 percent.
"Trump is targeting China, although he says the steel import probe has nothing to do with China," said Choi Moon-sun, a steel analyst at Korea Investment & Securities in Seoul.
"Only about 5 percent of South Korea's steel produce goes to U.S., so any impact will be very limited for Posco. China will feel the pain if there is any wider import restrictions."
Trump won many votes in industrial states like Michigan and Pennsylvania with a pledge to boost manufacturing and crack down on Chinese trade practices.
His move diverges from the Obama administration's approach to the issue, which relied largely on filing complaints to the World Trade Organization (WTO).
China is the largest national steel producer and makes far more than it consumes, selling the excess output overseas, often undercutting domestic producers.
Investors in most Chinese producers seemed to absorb the news well, in part because it had been so long telegraphed.
China's stock markets often march to their own drummer and, despite Trump's talk of massive dumping, U.S. steel demand really isn't that big of a deal for China.
The Asian behemoth accounts for almost a quarter of global steel exports, yet less than 1 percent of those exports went to the United States last year, according to data from the U.S. Commerce Department.
Shares in Baotou Steel (>> Inner Mongolia BaoTou Steel Union Co.,) were up 1 percent, while Angang Steel (>> Angang Steel Company Limited) added 0.3 percent and Baoshan Iron & Steel Co (>> Baoshan Iron & Steel Co Ltd) held steady.
Beijing has long pledged to downsize the industry which is plagued by oversupply from inefficient, high-polluting mills, but has baulked at the potential loss of jobs.
Many Chinese investors seem to favor a rationalization in production which would boost the price of steel as shares in lower-cost producers rally whenever cutbacks are floated.
"The key thing is that we don't know enough about this, and whether the Trump administration is somehow going to reduce the supply of steel coming out of China, because that would actually be positive for steelmakers everywhere and would increase steel prices," explained a director of equity cash sales at a foreign securities house in Tokyo.
Prices for steel and iron ore in China were indeed rallying on Friday, after a rough few weeks when fears that production was starting to outstrip domestic demand hammered markets.
Inventories are swelling, adding to fears of a supply glut later in the year.
China's crude steel output reached a record 72 million tonnes in March as mills ramped up output.
Its exports of steel products rose about 32 percent to 7.56 million tonnes in March from February, when they were at a three-year low.
(Reporting by Wayne Cole; Additional reporting by Dahee Kim, Cynthia Kim, Nichola Saminather, Lisa Twaronite; Editing by Kim Coghill)