Tsunami sirens were due to sound at 6am local time Saturday (3am Sunday AEDT) to alert residents of the possibility of destructive waves, forecast to reach the islands by 11.19am Saturday local time (7.19am Sunday AEDT) , according to emergency management officials.
"If you live anywhere in the evacuation zone, you have to evacuate," John Cummings, Oahu Emergency Management Department spokesman, told local media.
"We're going to treat this as a destructive-type tsunami."
It is the first time Hawaii has experienced voluntary tsunami evacuation since 1994. Emergency services have fleets of public buses to provide free transport for anyone needing to leave evacuation zones.