If you want to buy a brand-new apartment in Manhattan in the next five years, it will be expensive and pickings will be slim, according to a new development report released yesterday by real estate site CityRealty.

The site found that ultra-luxe inventory will dominate the new construction market in the next half-decade, with five buildings expected to account for $10 billion in the city sales market.

Rising prices in new construction is nothing new to New Yorkers, as the price-per-square-foot in that market jumped 50% from 2013 to this year, according to CityRealty. That's expected to continue; its report predicts that a new apartment in Manhattan will go for an average of $5.9 million in 2015, more than double the overall average of $2.7 million.

Despite the big numbers in sales costs, the expensive price tags are driven by low numbers in new inventory, CityRealty director of research and communications Gabby Warshawer explained.

"There aren't that many buildings made with a lot of units," she said, adding that this is because apartments built today are bigger than in the past. For example, the new high-rise at 432 Park Ave. has 104 medium-sized units, she said, compared with The Orion, built in 2006, which has 551 smaller ones. According to CityRealty, 1,200 sales closings are expected for 2015, less than half of the volume sold in the market's peak in the mid-2000s.