Hawai'i's special congressional election to replace outgoing Rep. Neil Abercrombie may be delayed beyond May 1 because of the time it takes to buy voting machines, deal with legal challenges and mail ballots.

The state Elections Commission yesterday appointed Scott Nago as its new chief elections officer through Feb. 1, 2012. One of his first tasks will be to schedule a special election to fill the remaining 10 months of Abercrombie's term while Abercrombie campaigns full time for governor.

Nago, who had been interim elections head, yesterday said he still hopes to hold the vote-by-mail election May 1, but that any challenge of the pending selection of a new voting machine company would immediately halt the process.

Abercrombie, a Democrat, has said he'll resign on Feb. 28.

The special election will cost about $1 million, and the elections office is asking Gov. Linda Lingle's administration to find that money by shuffling funds, releasing budgeted elections cash, seeking new appropriations and spending Help America Vote Act savings, Nago said.

Buying new voting machines could slow the process. The state must get new machines because of a ruling that it overpaid on its previous contract; $2.8 million was allocated for the new machines last year.

The elections office plans to award a voting-machine contract by March 23, but a protest from any company that loses its bid could take 45 days to resolve, Nago said. Even though the special election will be held with mail-in ballots, voting machines are still needed to count them.

A bill up for vote in the state House today sets up an alternate voting-machine buying process, in which a losing voting machine company would have five days to ask for reconsideration and Nago would issue a final decision within another five days.

Even in a best-case scenario, where all the money is made available and the voting machines are quickly purchased, it would still take time to hire temporary election workers, mail ballots and count them, said Honolulu City Clerk Bernice Mau.

"I don't think they could hold it May 1," Mau told the Elections Commission. "It's going to take time."

A June election is more likely, she said.

In January, the Elections Commission asked for a legal opinion on whether the state could save money by waiting until the Sept. 18 primary election to fill its soon-to-be-vacant congressional seat.

"The short answer to this question is 'no,' " wrote Deputy Attorney General Russell Suzuki. "We recommend that the special election be held as soon as practicable after the resignation of Congressman Abercrombie."

Nago had been serving as interim chief since Dec. 30, when Kevin Cronin resigned.

Nago will now serve out the rest of Cronin's term, which expires on Feb. 1, 2012,

Nago had led the ballot- counting section for the state Office of Elections, and his appointment to interim chairman was endorsed by the four county clerks.

"Scott has proven himself," said William Marston, chairman of the state Elections Commission. "He's a good man. He's already showed his worth, and he has our support 100 percent."