Sales of existing homes on O'ahu continued to tumble in September, but median prices were about 5 percent higher compared with the same month last year.

The median single-family home resale price last month was $650,000, up 4.8 percent from a year ago but unchanged from August, according to sale data compiled by the Honolulu Board of Realtors.

September's median condominium resale price was $335,000, up 4.7 percent from a year ago to tie a record set in July. In August, the median condo resale price was $325,000.

Prices stayed firm despite a hard drop in sales.

Single-family home sales fell 29 percent — the biggest percentage-point decline since sales began their general descent about two years ago.

There were 255 single-family homes sold, compared with 359 a year earlier.

Though sales from month to month are affected by seasonal patterns in home buying, September's sales tally was the lowest for any month since February 2006.

Condo sales totaled 414, down 13.9 percent from 481 during the same comparable period. The last time sales were lower was in February, when 402 units sold.

Some of the decline in sales, according to industry analysts, may be a result of the fallout from the subprime mortgage lending crash earlier this year. That's reduced mortgage options for buyers with less than prime credit or no down payment, but it has been difficult to quantify the impact on sales.

Berton Hamamoto, president of Property Profiles Inc. and the Honolulu Board of Realtors, said that despite declining sales volume and some rising inventory, median prices have remained relatively constant.

For the first nine months of this year, single-family home sales are down 7.4 percent to 2,877, and the median price is up 2.2 percent to $648,000.

Year-to-date condo sales are down 13.9 percent to 4,344, and the median price is up 4.8 percent to $325,000. The median price is a point where half the sales are for more and half for less.

"The housing market on O'ahu appears to be a in a general slowdown, similar to the Mainland markets, although we've not experienced the price declines," said Harvey Shapiro, research economist for the board.

Quincy Kaneshiro, an independent real estate agent, isn't so sure prices won't decline. He said the curtailing of subprime lending earlier this year has reduced the pool of buyers and made homes less affordable, which puts negative pressure on prices.

The University of Hawai'i Economic Research Organization last month projected that O'ahu's median single-family home resale price will end the year 0.97 percent higher at $638,160, then decline 0.63 percent next year to $634,150.

The organization's projection for condo median prices is for a 5.19 percent rise this year to $326,360, followed next year by a 0.73 percent decline to $323,970.

Reach Andrew Gomes at agomes@honoluluadvertiser.com.