Hong Kong's panda pair of Ying Ying and Le Le have finally produced babies, after they successfully mated in March this year at Ocean Park.

After five months of pregnancy, Ying Ying gave birth to one female and one male in the small hours of Thursday. Ocean Park, where the giant panda lives, said she spent much of her time lying on the ground and twisting, and that she was in labour for more than five hours.

"Ocean Park Hong Kong is thrilled to welcome the birth of the first-ever giant panda twins in Hong Kong," the amusement park said on its Facebook page.

"This birth is a true rarity, especially considering Ying Ying is the oldest giant panda on record to have successfully given birth for the first time," the park said, adding that she gave birth just one day before her 19th birthday.

"Both cubs are currently very fragile and need time to stabilise, especially the female cub who has a lower body temperature, weaker cries, and lower food intake after birth. Currently, both babies are under 24-hour intensive care by the park’s animal care and veterinary team, as well as experts from China Conservation and Research Center for Giant Panda."

Meanwhile, Chief Executive John Lee called the birth of the panda twins a very special occasion, and thanked the nation for having gifted Ying Ying and Le Le to Hong Kong.

He also thanked Ocean Park's team for taking good care of the city's giant pandas and experts from the research centre for their support.