He said George FM would not be what it is today without the music of all the DJs who "put in the hard yards, many of whom have been recently unceremoniously dropped in the same way".
He thanked everyone who had listened each week and texted in over the years.
MediaWorks, the owner of George FM, did respond to requests for comment about Evans' claims.
Days after announcing they were hiring Mr Key, the station sent an email to staff warning them not to criticise their colleagues, or face being taken off air.
"As a direct requirement for anyone wishing to maintain a show at this station, ANY and ALL social media relating to the new George FM Night time residents and schedule must be positive," it said.
MediaWorks declined to comment on the email.
George FM DJ Aroha Harawira spoke out in support of Key, saying he should be judged on his musical ability and not his father's politics.
"I haven't met Max Key yet myself, I've never seen him DJ, but I heard him on George FM last night and I thought he played a pretty sweet set," Harawira wrote on her blog site.
"I value my friends' opinions and I'll give the guy a chance. I think you should too ... Say what you want about John Key, but leave his kids out of it."
Mr Key is to host a one-hour show on Tuesday nights and starts next week.
He is to unveil his new single, Forget You, rumoured to be about his recent split from Amelia Finlayson.
In an interview on the station, Key said he'd been working on his material on his own, and he was "super excited" to release it.
Co-host Jay Bulletproof said he had heard the song, and it was an "absolute banger".
"I'm proud to say I'm releasing my first single Forget You. Previewing on my first show on George fm nights, Tuesday the 16th at 10pm ... I can't wait to drop this," he wrote on Instagram.
- nzherald.co.nz
