An animal welfare group says the first Bornean orangutan twins to be born at the city's Zoological and Botanical Gardens should be released into the wild.
The pair, a male and a female, were born last Friday weighing 2kg and 1.4kg respectively.
They were born to Vandu, a 16-year-old male orangutan transferred from the Sosto Zoo in Hungary in January last year, and Raba, 15, a female born locally in 1996.
They are now being cared for by veterinary officers until they are old enough to be seen by visitors.
But the Society for the Prevention of Cruelty to Animals says it is wrong to keep the twins in Hong Kong. Spokeswoman Rebecca Ngan Yee-ling said the climate is not suitable and the facilities are sub-standard.
She also said the twins should not be transferred to another zoo overseas but should be freed into the wild.
She said: 'It was wrong to bring Vandu here and it was more wrong for them to have babies.