TOKYO (AFP) - A pop star with ageing Japanese boy band SMAP was arrested for public indecency, police said, amid reports he was naked, drunk and acting erratically in a central Tokyo park.

Tsuyoshi Kusanagi, 34, was arrested early in the morning near the Roppongi nightclub district after a local resident alerted police, a police spokesman said.

Television stations reported the arrest by flashing bulletins usually reserved for earthquakes and other major events, while television helicopters filmed the park from the air after sunrise.

"What's wrong with being naked?" Kusanagi reportedly yelled at a police officer who approached him.

The incident infuriated Communications Minister Kunio Hatoyama, whose ministry has featured Kusanagi in its campaign to promote the 2011 start of nationwide terrestrial digital broadcasting.

"If the report is true, I'm immensely angry... I'll drop him off everything related to terrestrial digital broadcasting," he told reporters. "I'll never forgive him."

Boy band SMAP gained fame from the early 1990s and became hugely popular in Japan and elsewhere in Asia with a string of chart-topping hits.

Its members have used their fame to get roles in television dramas and movies, and Kusanagi has starred in films and featured in many commercials.

In South Korea, he is better known as "Cho Nan Kang" and liked for his good command of the Korean language.

SMAP, one of many successful pop groups formed by Japanese talent agency Johnny and Associates, is an acronym for "Sports Music Assemble People."