More than $5 million worth of watches have been stolen from a Singapore shop, the dealer said, in a rare crime of such magnitude in one of Asia's safest cities.

Cortina Holdings Ltd, which has outlets in Southeast Asia, Taiwan and Hong Kong, said it discovered the theft last Friday.

"The theft involves timepieces at a net cost of about 7.9 million Singapore dollars ($5.5 million)," Cortina said in a statement late on Monday to the Singapore Exchange.