It is thought Barry and Tame will shortly be announced as the new hosts of Breakfast - but they won't be on air together until next year.
Williams, who has worked at TVNZ since 1979, will continue to read the news at weekends.
A representative for TVNZ yesterday declined to answer questions about Williams' departure from the show, other than saying "we have no comment to make on the latest speculation".
The news of Williams leaving the morning airwaves marks another twist in a turbulent fortnight at Breakfast.
On July 9, after months of speculation over the future of the show - initially sparked by Barry's resignation from MediaWorks in April - sources told the Weekend Herald Christie and Chalmers-Ross had learned they would be going the day before when called to a meeting with news boss John Gillespie.
Later that afternoon Christie, Chalmers-Ross and Williams were spotted drinking at a central Auckland bar. Several people were said to be commiserating with them. Sources told the Herald that Christie and Chalmers-Ross were upset.
Both declined to comment on the moves, while Williams said he had "no idea" about any changes to the Breakfast show.
"I am going to work tomorrow as usual and as far as I am aware I still have a job to go to," he said at the time. "No one has told me anything different," the Mastermind host said.
Last weekend, a top employment lawyer told the Herald on Sunday Christie could have avenues to seek damages for humiliation, loss of dignity and injury to feelings after his public axing from Breakfast.
"Depending on the circumstances, Rawdon may be entitled to bring a personal grievance against TVNZ for unjustified disadvantage and ... unjustified dismissal," Jennifer Mills, head of national employment law practice at Anthony Harper, said.
"A successful claim would then entitle him to claim for a range of remedies under the Employment Relations Act 2000, including damages for humiliation, loss of dignity and injury to feelings."
For damages to be awarded, the Employment Relations Authority must find TVNZ's actions were unjustified in some way, Mills said.
Christie had been missing from the Breakfast couch this week, but TVNZ said yesterday he was on leave and would be back on air on Tuesday.
Yesterday, Williams could not be reached for comment.