In a housing crisis that shows no end, the Chinese government is stepping in as a buyer of last resort.

Chinese officials on Friday took their boldest step yet, unveiling a nationwide plan to buy up some of the vast housing stock languishing on the market. They also loosened rules for mortgages.

The flurry of activity came just hours after new economic data revealed a hard truth: No one wants to buy houses right now.

Policymakers have tried dozens of measures to entice home buyers and reverse a steep decline in the housing market that has shown few signs of recovering soon.

On Friday, authorities from across China dialed in to a video conference to discuss the challenges they faced. China’s vice premier, He Lifeng, announced a substantial shift in the government’s approach to dealing with the housing crunch, which has prompted households to cut spending. Mr. He said that local governments could begin to buy homes to start dealing with the huge numbers of empty apartments.

The government-purchased homes would then be used to provide affordable housing. Mr. He did not provide any details on when such a program would begin or how it would be funded.