About 30 soon-to-be Toyota Prius owners on O'ahu are leaving their hard-to-get hybrid cars on dealers' lots through December so they can qualify for 2006 tax breaks.

By picking up their gas-electric hybrids after the New Year, buyers will qualify for tax credits that could lower their income tax bills by as much as $3,150, according to an analysis by the American Council for an Energy-Efficient Economy.

While other hybrid buyers also would qualify for tax credits, the Prius' 60 mile-per-gallon city rating makes it likely to qualify for the maximum credit.

The phenomenon of ordering the hybrids in 2005 but taking ownership in 2006 is almost exclusively reserved for the Prius and began only this month, said Rick Ching, senior vice president of Servco Pacific, Inc., which operates all of the Toyota dealerships on O'ahu and one on Kaua'i.

"The cars are ready to go but the customers don't seem ready to take delivery," Ching said. "Many of them have been waiting for their vehicles for quite some time. ... It seems to be a December phenomenon. It didn't go back into November or October. I guess when you get so close to the end of the year, it's only a couple more weeks."

Toyota spokeswoman Nancy Hubbell said it's a nationwide trend for Toyota dealers.

"We have seen it all around the country," she said.

The wait time to buy a Prius in Hawai'i is generally three months, and dealers theoretically could sell them to the next person on the waiting list.

But Servco officials chose instead to continue paying the debt service on the cars themselves — and the extra costs to store, wash and detail them for at least another week, Ching said.

"Some dealers might say, 'If you don't take delivery we'll sell it someone else,'" Ching said. "We made a conscious decision not to do that. It's a tough one. If it had been back in October, we would have had a more difficult decision."

Reach Dan Nakaso at dnakaso@honoluluadvertiser.com.