Confronted with takeover-defense measures adopted by Japanese companies, Warren Lichtenstein, the head of U.S. hedge fund Steel Partners, urged Japanese investors Tuesday to consider the downside of such "poison pill" tactics.

"We believe that poison pill is illegal and discriminates against shareholders," Lichtenstein told a news conference in Tokyo. "It's (still) new (in Japan) and so people don't understand."

With stakes in more than 30 Japanese companies, Steel Partners Japan is one of the most prominent U.S. activist hedge funds here. It is the biggest shareholder in such firms as Worcestershire sauce maker Bull-Dog Sauce Co., wig maker Aderans Co., brewer Sapporo Holdings Ltd. and Nissin Food Products Co.