Chief medical officer Sir Frank Atherton and former NHS Wales boss Dr Andrew Goodall will be questioned.
Both men were key to Wales’ Covid response, appearing regularly in live televised media briefings.
First Minister Mark Drakeford and the then-health minister Vaughan Gething are due before the inquiry on Tuesday.
Mr Gething became economy minister in May 2021 while Dr Goodall is now the Welsh government’s permanent secretary, its most senior civil servant.
Covid in Wales: What do the stats tell us?
What is the UK Covid inquiry and how long will it take?
The hearings, chaired by former judge and crossbench peer Baroness Hallett, have heard accusations from the Covid Bereaved Families for Justice Wales group that there was a “catastrophic failure” to plan for such an emergency by Welsh ministers.
Giving evidence on the first day of the inquiry last month, the group said the Welsh government “do not appear to have taken sufficient steps to understand and plan for the risks of a pandemic”, despite UK-wide warnings.
The group’s barrister, Kirsten Heaven, said this had led to “much more severe consequences from Covid-19 for vulnerable groups and communities”.
The group also accused the Welsh government of trying to “shift responsibility” for pandemic planning on to the Senedd and civil service.
