The four new hires will host new shows on the revamped Magic Talk, due to go live early next year.
Gusto, a new station aimed at 40-54 year-olds, and Rush, a channel targeting the adventure genre, will go to air in March next year.
With Newstalk ZB as strong as ever and MediaWorks rapidly assembling a strong team of broadcasters, RNZ faces a fight to return to its 2020 numbers.
Madison Reidy is leaving Discovery at the end of the year, the latest in a long line of departures from the US-owned channel.