Laura Magahy and Tom Keane stood down from their roles on Wednesday,
11 members of the Sláintecare Implementation Advisory Council say they are concerned following the "shock" resignation of 2 senior officials from the group.
Laura Magahy and Tom Keane stood down from their roles on Wednesday, saying that requirements for the plan were seriously lacking.
Sláintecare commits to end private practice in public hospitals and provide universal healthcare and free GP care.
The council says it is actively seeking answers from the Department of Health about the events that led to the 2 senior members standing down.