Doctors and parents of a four-month-old girl who's in desperate need of a heart transplant on Friday made an urgent appeal for a heart donation.

The Hong Kong Children’s Hospital said the girl is suffering from dilated cardiomyopathy – a condition in which the heart becomes enlarged and cannot pump blood effectively.

The baby’s doctors said she’s been put on a ventilator and is currently in critical condition.

They said the heart should come from a brain dead child who’s under 13 kilograms.

"Then, there are other criteria, such as the heart donor cannot have some types of cancer and uncontrollable infections," said Lun Kin-shing, who's the consultant-in-charge of the hospital's cardiology team.

Another doctor on the team, Nicholson Yam, conceded that it is very hard to find a suitable donor.

"We will consider heart donors whose body weight is up to three times that of the girl as the number of suitable heart donors is very limited. And as the immune system of infants has not yet matured, the protocol we established is, we will accept donors aged two or under regardless of their blood type," Yam said.