The National Public Health Emergency Team has called for 90% of over 16s to be fully vaccinated before a further widespread easing of restrictions, it is understood.
The criteria is contained in the group's latest letter to the Government containing recommendations on the next stage of the pandemic.
One Government source said there was surprise at the request and that it was a very high threshold. It is likely to take another six weeks to meet that target.
In the letter, NPHET said that once the threshold is reached, a switch could take place from a focus on regulations to public health advice and personal judgment.