The volume of home sales on Nassau County’s storm-ravaged South Shore plummeted late last year, even as sales and prices jumped along the county’s North Shore.

Real estate transactions on Nassau County’s southern coast dropped by 23.5 percent in the past three months of 2012, compared with the same period a year earlier, according to a report scheduled to be released Thursday by the appraisal firm Miller Samuel and the brokerage Douglas Elliman. The southern coast’s median sales price was $350,000, a 2.8 percent year-over-year decline.

The time period covered by the report includes the Oct. 29 landfall of superstorm Sandy, which destroyed tens of thousands of homes and derailed many scheduled home sales.

The storm’s effect on sales volume in the area could be only temporary, since many transactions might have been delayed until 2013 as lenders demanded new appraisals, said Jonathan Miller, chief executive of Miller Samuel.

The Nassau southern coast’s price decline is probably because the storm delayed or canceled many sales in waterfront communities, where prices tend to be higher, Miller said.

“The rebuilding is going to take a year or two,” Miller said, “so I think it will be a gradual phase-in back to historically reasonable sales levels.”

It’s too soon to tell what impact Sandy has had on prices of homes contracted for sale after the storm hit, since most of those sales hadn’t closed by the end of the year.

Across Long Island — excluding the East End — the median home price rose by 3.2 percent, to $350,000, in the October through December quarter, compared with the same period in 2011, according to the report. The number of home sales rose by 7.5 percent, according to Miller Samuel.

The number of homes on the market dropped by 21 percent, which Miller attributed to homeowners having little or no equity and thus having no motivation to sell, along with tight credit.

Dottie Herman, chief executive of Douglas Elliman, expected Sandy’s impact to be short-lived, and largely confined to the areas that took a direct hit. “If we had another hurricane of that magnitude in the next year it might have an impact,” she said of Sandy. The storm’s impact still lingers in certain communities, such as Long Beach and parts of Merrick and Massapequa, she added.

The bigger problems facing the Island’s housing market are high property taxes, the sluggish job market and tight credit, Herman said.

Meanwhile, on Nassau’s North Shore home sales surged by 27.7 percent in the fourth quarter, compared with a year before. The North Shore’s median price rose by 10.5 percent, to $718,250.

The steep rise in sales and prices along Nassau’s Gold Coast reflects an effort by sellers of luxury homes to close transactions by the end of 2012, to avoid a rise in capital gains taxes in 2013, Miller said.

Hamptons home prices jumped by 16.3 percent, to a median of $907,000, as transactions accelerated before the capital gains tax increase, he said.

In the past 10 years, the median price of a one- to three-family home on the Island — outside of the East End — has not budged, from $345,000 in 2003 to the same number last year, according to Miller Samuel and Douglas Elliman.

“This was one of the longest housing booms in history, which created a very hard landing that we’re just now getting out of,” Miller said.