Ghosts hover nearby as he works, Mr. Wong said, invisible beside the family members who gather at this reverse funeral, but he says he knows the spirits well by now and is not afraid.

Mr. Wong’s exhumations are part of a redefinition in much of Asia of the concept of burial. This is a continent where ancestors are revered and their graves are places of worship, but where sheer numbers are straining funeral traditions.

With a population that is expected to rise by 40 percent, to 6.5 million, over the next half century, Singapore illustrates the growing scarcity in Asia of a fundamental resource, land.

In China, where arable land and urban space are in high demand, ground burial is prohibited in most of the country, although exceptions are made if a fine is paid.

“Space is so tight that something has to give,” said Lily Kong, director of the Asia Research Institute at the National University of Singapore, who has studied funeral practices. “And that means a shift throughout the region to crematoria and columbaria.”

But even the columbaria are now filling up, and residents in places like Hong Kong and Taiwan are resisting the construction of new ones in their neighborhoods, she said. “Essentially, it is a spatial competition between the living and the dead.”

Given this increasing demand, slots in columbaria have become real estate investments in Singapore, with companies promoting block purchases and zero-interest payment plans.