A lack of new homes is making O'ahu's already tight housing market even tighter.

In the first half of this year — one of the hottest periods Hawai'i's real-estate market has ever seen — there was a 28 percent decline in new home sales, not because of a shortage of buyers, but because of a lack of supply.

"My initial thought is: What's the matter with developers?" said Ricky Cassiday, a market researcher who compiled the sales statistics for Hawaii HomeLoans. "They're not pumping out homes this year."

Home builders contracted to sell 1,222 new homes this year through June, the lowest tally for a January-June period since 2002, according to Cassiday. Prices, meanwhile, rose to an average of $544,829, a 16 percent gain.

The inventory of new homes at the end of June was 738, down 43 percent from 1,303 a year earlier.

The inability to find new homes has led people such as Elizabeth Fitzgerald, a former North Shore resident, to the resale market where inventory also is tight.

Fitzgerald, who was selling her Turtle Bay condominium because she was tired of her three-hour roundtrip commute to work, reserved a unit in the planned 909 Kapiolani condo in Kaka'ako last year. But a delay at the project led her to buy a condo unit at the existing One Waterfront Towers nearby. "I needed a place to live," she said.

The decline in new home sales and inventory is in contrast to the resale market, where purchases of previously owned homes on O'ahu were up about 4 percent during the first six months of this year and prices were up roughly 25 percent. The median price for previously owned homes hit a record high of $610,000 in May.

Cassiday said the slowdown in new home sales was primarily caused by a delay at the 909 Kapiolani high-rise and a single-family home inventory shortage for Castle & Cooke Homes in Central O'ahu.

The 909 Kapiolani high-rise began taking sales reservations in April 2004, but construction pricing difficulties have delayed converting reservations to binding sales for the 225-unit tower.

At Castle & Cooke, sales have been reduced for the company's Mililani community after largely selling out the Renaissance and Royal Kunia subdivisions in Waipahu, according to Bruce Barrett, principal broker and vice president of sales and marketing for Castle & Cooke.

"Basically Mililani has been carrying us for the first six months of the year," he said.

Castle & Cooke's Island Classics project in Mililani accounted for 94 sales in the first half of the year, the highest-selling single-family project on O'ahu, Cassiday reported. But overall, O'ahu sales for Castle & Cooke fell to 135 during the period, compared with 320 during the first half of last year, Cassiday's said.

The next project for Castle & Cooke, a 275-home subdivision called Wai Kaloi in Makakilo, won't be ready for sale until October. "We'll be back into higher numbers with that community coming out," Barrett said.

O'ahu's other major single-family home developers produced modest sales increases during the first six months of the year, according to Cassiday, who expects home builders to regain some lost ground later this year as the latest condo high-rise projects begin to execute binding sales contracts.

(Cassiday's report counts sales when buyers cannot cancel without losing a significant deposit, as opposed to when the home is transferred to the buyer, which can take anywhere from six months to two years because of construction.)

Among condo high-rise projects that could begin to lock in sales later this year are Keola La'i in Kaka'ako, Capitol Place downtown, The Pinnacle Honolulu downtown and 909 Kapiolani.

"I think the numbers will bounce back up," Cassiday said. "The demand is there."

The biggest selling new single-family home projects after Castle & Cooke's Island Classics were 68 sales for Ke'alohi Kai by Haseko Homes at Ocean Pointe, and 53 sales for Prescott III in 'Ewa Beach by Gentry Homes.

Top sellers for new multifamily home projects were Spinnaker Place at Ocean Pointe with 114 sales followed by The Colony in Hawai'i Kai by Stanford Carr Development. Kaka'ako high-rise Ko'olani by Crescent Heights and Ko Olina Kai by Centex Destination Properties each had 78 sales.

Reach Andrew Gomes at agomes@honoluluadvertiser.com.