The founder and chief executive of foreign workers' advocacy group Humanitarian Organisation for Migration Economics (Home) Bridget Tan is in intensive care after suffering a stroke on Wednesday morning.
Ms Tan, 65, was sent to Changi General Hospital on the same day, after collapsing in her home. She remains unconscious as of Wednesday evening.
The Archdiocesan Commission for the Pastoral Care of Migrants and Itinerant People took to its Facebook page to call on people to pray for Ms Tan.
"She collapsed at her home this morning and was taken to hospital. She is suspected of suffering from a stroke arising from a blood clot in her brain. Please pray for her," it wrote.
Ms Tan founded Home in 2004 and served as its president until two years ago. In Oct 2012, she stepped down and took on a newly-created position of chief executive officer, where she managed the daily operations of the group.