Do we need to wake up the newborn infant every 2 hours for feeding or feeding on demand is sufficient for a newborn?

Waiting until your newborn is awake is generally sufficient, as "feeding issues" are usually the stimulus needed for wakefulness in newborns. If such sleep intervals are much beyond 2-3 hours prior to wakefulness, ask your pediatrician for guidance.

I wake newborns to feed at least every 3 hours if they are under 8 pounds. After they reach 8, I let them decide when to wake and eat. This assumes the kid is acting normally/sleeping/feeding/playful some/etc.