SINGAPORE - Prime Minister Lee Hsien Loong has shared old photographs of his father Lee Kuan Yew online, and asked netizens to help supply information about them.

The photos of the former prime minister are from the National Archives of Singapore (NAS), which has uploaded materials on a new Citizen Archivist Portal.

The public can go on the portal to describe images or transcribe documents in the crowdsourcing project.

"I browsed the collection, and spotted my father in this set of photos. I think they were taken on election day on 21 September 1963, days after Singapore joined Malaysia.," he wrote.

Mr Lee, 91, has been at the Singapore General Hospital since Feb 5 when he was admitted for severe pneumonia.