Commissioner for Primary Healthcare Pang Fei-chau on Thursday said it isn't a major issue that only a few hundred doctors are set to take part in the government's Chronic Disease Co-Care Pilot Scheme.

The administration said it expected 1,000 private doctors to join up for the programme, which will provide subsidised screening and treatment for diabetes and hypertension in people aged 45 and above.

However, only 300 doctors are signed up, with just days to go before the scheme launches.

Pang told RTHK's Hong Kong Today programme that the number of doctors will gradually increase when there's more awareness of the programme.

"In the longer term, of course we have more measures to be implemented. We would send letters to the doctors that when the people come to district health centres, and say doctors who are not at the moment on the list, then we would invite those doctors and hope to pair them with the patients they like," he said.

"This scheme involves a lot of different subsidies so we understand that the doctors will need more time to understand details and change the way of their practices at their clinics."

Pang added that the programme is designed to boost preventative medicine and ease the burden on the public healthcare system.

"More than 70 percent of the people aged over 45 with either undiagnosed hypertension or diabetes, and also have additional 5.5 percent of population that aged 45 have undiagnosed pre-diabetes, so through this screening programme, we hope to have early diagnosis of those disease and so we can have early intervention to prevent the complications."