On Tuesday it announced it was cancelling long-running magazine show Good Morning, affecting about 15 staff and contractors, including host Jeanette Thomas.
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Oliver-Kerby is in the United States until the end of the month and could not be reached for comment yesterday.
Williams said he had "absolutely nothing" to say about the proposal.
"I can't make any comment whatsoever."
Williams, who also reads the news on Breakfast from Mondays to Wednesdays, is widely regarded as one of the network's most popular presenters.
Former sports presenter Oliver-Kerby also reads the weekday news on Mike Hosking's top-rating Newstalk ZB breakfast show.
Olsen said yesterday she could not comment on whose idea it was for her to leave.
There is speculation Renee Wright could take on weekend weather duties, with Dan Corbett becoming a weekday staple.
It's understood the changes proposed yesterday include the scrapping of three camera operator roles, two director of coverage positions and a reporter's position in Dunedin.
A spokeswoman said the network had "entered into consultation with a small number of news and current affairs staff" but Olsen's departure was unrelated".
TVNZ cannot comment on specifics relating to proposed newsroom changes at this point in time as we are in consultation with staff and the process is subject to change.
"A statement from head of news and current affairs John Gillespie said the proposals would see "some possible staff redeployment" and "an estimated eight to 10 roles impacted".
The proposals were about TVNZ continuing to refine its news-gathering processes, he said.
"Technology efficiencies and news-gathering changes mean we can, and have to, operate our business differently in order to continue to be successful.
"Our focus on credible journalism and delivering the moments that matter to New Zealanders on all platforms will not change."
Olsen has been with the broadcaster for 22 years, having previously worked as a meteorologist with MetService.
She will be on air until early November.
She said yesterday she wasn't sure about her next move, apart from spending summer with her family.
"I've had a wonderful time at TVNZ and I've had a lot of opportunities with them. I work with a wonderful bunch of people and I will miss the crowd I work with.
"This has happened and I'll move on. I've got no hard feelings towards TVNZ and I've left on good terms," she said.
"These things have happened fairly quickly and I'm just going to enjoy the summer."
Olsen said she'd had many chances at the broadcaster she otherwise wouldn't have received, such as flying with the Red Checkers and reporting from interesting places, such as Antarctica, and on major weather stories.
She had learned a lot, having started as a scientist with no broadcasting experience.
"I will miss presenting the weather. It's been a job that I have loved. Every day is different."I'm a bit of a weather nerd. I love the weather."
Mr Gillespie said Olsen would be missed by viewers and colleagues.
"Karen's knowledge as a meteorologist and her dedication to broadcasting has been top rate, we'd like to thank Karen for her service to New Zealand audiences and TVNZ."
