A briefcase containing opals and pearls worth about $1.5 million was stolen from a dealer two hours before Asia's biggest international jewellery fair opened.

The 63-year-old woman, from Australia, was approached by a stranger at 8am on the first floor of Convention Plaza, near the Convention and Exhibition Centre in Wan Chai, the venue of the Hong Kong Jewellery and Watch Fair. The man asked her to help him pick up some cash on the floor. Afterwards she realised one of her three briefcases had disappeared.