Former City Councilwoman Ann Kobayashi said last night that she will vie for her former council seat, which was left vacant last week by the sudden death of Councilman Duke Bainum.

If she wins re-election to the council, Kobayashi said, she would not resign the seat as she did once before to run for any potential mayoral vacancy.

Kobayashi's resignation from the 5th Council District seat last year to challenge incumbent Mayor Mufi Hannemann created the opening for Bainum to win his own re-election to the council.

"It's not fair to the district to (be elected and) then run for mayor," Kobayashi said.

Kobayashi, who is on a long-planned visit to Italy with her family, said she is scheduled to return to Honolulu on June 22.

"I'll pick up my (nomination) papers that day, get the required 15 signatures and probably file the next day," she said.

The deadline for candidates to file for the all-mail ballot election is June 25. By law, the council must hold an election to fill the vacancy within 60 days.

Kobayashi held the 5th Council District seat, which encompasses Palolo, Kapahulu, Manoa and Makiki, from 2001 until last July.

Last week, Hannemann told supporters he has started an exploratory committee to determine whether he should run for governor in 2010, as well as to raise contributions for such a campaign.

Kobayashi said she flew out of Honolulu Wednes- day, the day the news broke that Bainum had died from complications due to an aortic aneurysm the previous evening.

On the plane ride to San Francisco, Kobayashi considered the possibility, she said. When the flight arrived, a couple on board urged her to run.

Since then, Kobayashi said, she has spoken to her daughter, Susan, and other supporters about a possible run. She's also had "many messages on my phone from people ready to get back on the campaign."

City Managing Director Kirk Caldwell has been mentioned as a possible candidate for the seat. Caldwell, the former majority leader in the state House of Representatives, resigned his House seat last July in order to run for the 5th Council District seat, only to be ruled ineligible.

Caldwell has declined to comment publicly about his intentions, saying he wants to respect Bainum's family.

State Rep. Scott Nishimoto, D-21st (Kaimuki, Kapahulu) also has been mentioned as a possible candidate but indicated he would not run if Kobayashi does.

A voter registration deadline for the election is July 8. The City Clerk's Office is expected to begin mailing ballots shortly thereafter. The deadline for ballots to be returned to the clerk is Aug. 7.

The term expires in January 2013.