A Chinese man who stole hundreds of pieces of ladies' underwear had his secret exposed after an emergency exit ceiling where he had been storing his hoard collapsed, state media reported.

The man, surnamed Tang and in his 30s, admitted to having mental problems since he was young and that he did not know how long he had been obsessed with women's undergarments, reports said.

Police in the city of Yulin said they found more than 2,000 pieces of panties and bras in the roof where he had stuffed his collection.

Residents in the housing complex where Tang lived had complained about the mysterious vanishing of their undergarments.

Tang used a master key for the apartments in the complex to sneak in and steal the underwear when residents were not there, media said this week.