Former presenter Steve Gray - who was dumped from Good Morning in 2009 - said it was another "stupid" move by TVNZ.
"We don't have actors. The guests are real people and [Pongia] is always fantastic at making them not worried and getting the best out of them on air, which is a really rare talent."
He said TVNZ was notorious for getting rid of valuable staff.
TVNZ spokeswoman Megan Richards would not confirm the decision to dump Pongia.
"We are still going through the auditioning process and have no confirmation of anything at this stage. We are not ready to make any announcements about any changes just yet."
Pongia told the Herald on Sunday he wanted to comment but his contract would not allow it.