The waves caused a stage to collapse in the Tanjung Lesung beach resort while holidaymakers and locals were watching the Indonesian pop band Seventeen.
One member of the band has been confirmed dead as well as the manager, according to the Jakarta Post. The newspaper said all the other band members were still missing.
Even though Indonesia was the worst country affected by the devastating Boxing Day 2004 tsunami that killed hundred of thousands of people, it still lacks the proper equipment to alert that a tsunami threat is coming.
"We need multi-hazard early warning system," Nugroho said. "And we need lots of it."