He has since been working from a home studio at his house in Christchurch,
He said his family were "enormously grateful" for all the "love, cards and prayers" they had received.
The Barnetts have been married for more than 25 years and have four children together, Sammy, Sophie, Bella, and Lily.
It is unknown when Barnett will return to work in a greater capacity, but a MediaWorks spokesperson confirmed to Stuff that he would be "dialling in on a regular basis" to provide updates while his wife underwent her treatment.
Barnett has hosted MediaWorks' More FM breakfast for two decades but is due to join Newstalk ZB next year.