PCCW Ltd., a telecommunications, media and technology conglomerate controlled by billionaire Richard Li, is mulling a significant minority stake sale in its fiber business for about $1 billion, according to people familiar with the matter.

The Hong Kong-listed company is working with a financial adviser on the potential transaction, the people said, asking not to be identified because the matter is private. The asset has drawn interest from Chinese investors as well as Middle Eastern sovereign wealth funds, the people said.