Sales of existing homes on Oahu were down more than 15 percent in June, and median prices were about flat or slightly lower, according to a Honolulu Board of Realtors report released today.

The number of single-family home sales fell 16 percent last month to 248 from 295 in the same month last year. The median price was down 3.4 percent to $562,500 from $582,500 in the period.

Condominium sales fell 20 percent last month to 354 from 442 a year earlier. The median price, which is a point at which half the homes sold for more and half for less, was up by just $1,000, or 0.3 percent, to $301,000.

Joyce Nakamura, president of the trade association, said the sales volume declines weren’t unexpected because activity in June 2010 was spurred by a federal tax credit.