Emergency sirens on O'ahu's North Shore have been upgraded to not only sound the alarm for tsunamis and other dangers, but to broadcast voice messages to tell people what's happening and what to do.

City and state emergency management officials will test the new voice-capable system from 9 to 11 a.m. today in Waialua and Hale'iwa.

The warning system uses existing outdoor warning sirens. The technology is in place only on the North Shore, but officials plan to roll out voice-capable sirens statewide by 2012.

The North Shore system was upgraded to warn residents if they need to evacuate because of high surf conditions, said John Cummings III, spokesman for the city Department of Emergency Management. The Waialua and Hale'iwa warning systems were added to address concerns raised during last year's floods.

"Right now, only these two and the group we have on the North Shore are actually set up to receive and broadcast a voice message," Cummings said.

As part of the upgrade, those sirens can be operated independently from the islandwide warning system.

"The future plan is that we'll be able to activate groups of sirens to warn communities for things like localized flooding events (or) in case there's a hazardous material spill and they have to evacuate the neighborhood," Cummings said.

Residents and businesses in the surrounding communities today may hear a series of chimes, followed by public-address voice messages during testing.

State Civil Defense money was used to buy and install the sirens.