China property vacancies have climbed to more than 20 percent of sold units, fresh data show, but analysts remain divided on whether a real estate crash is in the offing.

The numbers are high, with around 22.4 percent of sold residential homes in urban areas sitting empty in 2013, or a total of 49 million homes, while the number of unsold units is estimated at 3.5 million units, according to the Survey and Research Center for China Household Finance.