Hong Kong police are investigating an alleged theft of a diamond worth US$500,000 (HK$3.88 million) that reportedly went missing from a company safe in To Kwa Wan.

A man contacted the force at about 3pm on Thursday and said the gem had vanished from a safe in Peninsula Square on Sung On Street.

The man claimed the diamond was valued at US$500,000.

Officers visited the scene and started an investigation.

No arrests have been made.