Thieves eluded heavy security and made off with HK$300,000 worth of rings from a booth on the opening day of a major jewellery show in Wan Chai yesterday.
Another booth operator lost four gold necklaces worth HK$5,000, police said.
More than 100 police officers, in uniform and plain clothes, were deployed at the five-day 30th Hong Kong International Jewellery Show at the Convention and Exhibition Centre.
Also present were private security guards hired by the organisers of the show - Asia's largest spring jewellery fair.
Staff members manning the first booth noticed the rings were missing after several mainland men visited it at about 1.30pm.
"We believe the mainlanders stole the rings after distracting the employees' attention," a police officer said.