The World Trade Organization has yet to come up with a ruling on a steel dispute between the United States and an unprecedented number of economies, betraying initial expectations such a move would come as early as May.

The delayed interim ruling on the legality of America's controversial Byrd antidumping law has raised speculation within the Japanese government on the intentions of the Geneva-based global trade watchdog.

"I believe the interim ruling has been delayed for a purely technical reason," one senior trade official said, requesting anonymity. "The case is so difficult and complicated that panel members are taking more time than expected to hand down a verdict."