Health Minister Stephen Donnelly wants greater representation of scientists within the body, along with a more even gender balance than NPHET.
The new group, which will be officially announced later this week, will have no more than 14 members, compared to the 40 members that made up NPHET. Some NPHET members are expected to feature in the new group.
Meanwhile, Donnelly has ruled out introducing any new public health measures despite "hundreds of thousands" of new COVID infections being recorded each week.
He advised people to continue to wear face masks at "appropriate times" and for those yet to receive their booster jab to do so as soon as possible.
The minister highlighted how 60% of COVID patients in hospital have not received a booster shot.
"When you look at the numbers who are in critical care because of Covid, and who have had their booster vaccine, it’s likely in the late teens," he said of the impact of the booster.
"There still is an important role for masks even though the legal requirements have been taken away," he added, advising their use in crowded indoor settings and on public transport.
