Honolulu Prosecutor Peter Carlisle and City Council Chairman Todd Apo are seriously looking at the possibility of running for Honolulu mayor if Mayor Mufi Hannemann steps down to run for governor.

Hannemann last week authorized the formation of a committee to explore the possibility of a gubernatorial run in 2010. Hannemann would need to resign by July 2010 to do so, leaving two years on his term and triggering a special election.

"I'm seriously considering running for the office of mayor," Carlisle told The Advertiser yesterday.

Apo said "a lot of people" from the government sector and the business community have asked him to think about a mayoral run if Hannemann steps down. "So I'm considering it."

He added: "I'm enjoying the role I have right now as chair, and serving in that capacity, but I also realize there are a lot of other things that need to be done."

Apo said he wants to continue talking with his family about the situation but realizes he likely will need to make a decision soon, given recent developments.

If there is an opening for mayor, both men would need to resign from their current offices to run.

Carlisle, 56, was first elected prosecutor in 1996. He was elected to his fourth four-year term last year without opposition. That term runs through 2012.

Apo, 42, was elected last fall to his second term representing the 1st Council District, which includes 'Ewa, Kapolei and the Wai'anae Coast.

City law limits council members to two consecutive terms, so Apo could not seek re-election in 2012. There are no term limits for the prosecutor's post.

A third possible contender for mayor is city Managing Director Kirk Caldwell. The former state representative became Hannemann's second-in-charge earlier this year.

Caldwell, 56, has been on the Mainland and could not be reached for comment last night.

Earlier this week, when asked if he would run for mayor should Hannemann seek the governor's post, Caldwell said, "I will cross that bridge when he makes a final decision. But I feel that I'm learning a lot — the skill sets that you need to be a good mayor."

If Hannemann were to resign, Caldwell would serve as acting mayor until whoever is elected to replace him is sworn in sometime in January 2011.

Another possibility for Caldwell is to run for the City Council.

Caldwell said that he has still not made up his mind about running for the 5th Council District seat left vacant after Councilman Duke Bainum died suddenly on June 9.

When Ann Kobayashi chose to forgo a re-election bid to the 5th Council seat in 2008 to unsuccessfully challenge Hannemann for mayor, Caldwell chose not to seek re-election to the House and instead ran for the council seat. But Caldwell was declared ineligible, and Bainum was uncontested in the race.

Kobayashi has said she will run for her old seat and that she would not run for mayor.

Brian Schatz, chairman of the Hawai'i Democratic Party, called the potential race for Honolulu mayor next year "probably the most wide open political race in 2010."

Like all elected positions in the city, the mayor's post is nonpartisan.