The city Emergency Medical Services division on Sunday opened a new Central O'ahu ambulance unit that officials have said will improve response times to areas such as lower Mililani, Waipi'o and Waikele.

The new unit is based — at least for now — at Kaiser Permanente Hawaii's Waipi'o clinic, which is allowing the city to use the space rent-free. The unit will operate 16 hours a day, from 7 a.m. to 11 p.m., but officials will evaluate the unit to determine if there's a need to extend the service to 24 hours, EMS said.

The new ambulance unit "goes a long way" in expanding emergency medical services in the region, said Marty Burke, president of the Gentry Waipio Community Association and member of the Waipahu Neighborhood Board.

"The service is sorely needed," Burke said, noting the existing and planned growth in the Central O'ahu area. "It's such a valuable service, and we're just delighted to see it come in."

The Central O'ahu unit, staffed by at least two emergency personnel per eight-hour shift, has been seen as a necessary service for a region that not only experienced tremendous growth, but includes aging communities. Population has boomed in relatively newer areas like Mililani Mauka while residents in other Central O'ahu neighborhoods are growing older.

Call volumes have increased in the area, and the Waipi'o location was chosen because of its proximity to H-2 and Kamehameha Highway.

The unit responded to at least 16 calls on its first day Sunday, which is considered busy for a 16-hour operation, said EMS spokesman Bryan Cheplic.

EMS officials also said the unit will benefit other communities such as Wahiawa and Waipahu by allowing their ambulances to remain available for medical emergencies in their own regions. The unit may also on occasion handle calls in other areas.

"It is not inconceivable that the Waipi'o unit will cover calls anywhere on the island, from Wai'anae to Wailupe if need be," Cheplic said.

EMS dispatchers received 80,816 calls in the 2007 fiscal year that ended June 30, Cheplic said. An ambulance was sent out 74,887 times in that same period.

The Central O'ahu unit is the city's 19th unit.

State Rep. Ryan Yamane, an advocate for the Central O'ahu unit, said the call volumes more than justified the need for the unit.

"Our area is growing, so we really wanted to cover this ... Mililani and Waipi'o Gentry area," said Yamane, D-37th (Waipahu, Mililani).

Kaiser may eventually need to use the space that is now occupied by EMS, in which case Kaiser officials will give EMS ample notice, said Kaiser spokeswoman Jan Kagehiro.

Cheplic said EMS is "always looking for a permanent place" and that the Waipi'o unit will continue to operate in the community no matter what.

"Regardless if we're in Kaiser or not ... that Waipi'o unit will still continue to provide services in the community," Cheplic said.

Reach Lynda Arakawa at larakawa@honoluluadvertiser.com.