ZM was first started by the government-owned
Radio New Zealand as three separate AM radio stations in Auckland (1ZM), Wellington (2ZM) and Christchurch (3ZM) in 1973; however, all these stations had been on air under different identities in earlier decades. The Auckland 1ZM station changed format to
Classic Hits in 1987 and went on to become the first
Classic Hits branded station creating a 10-year absence of the ZM brand in Auckland. Wellington and Christchurch ZM stations carried on as two separate local stations, switching to FM and spawning their own regional networks. In July 1996 the
New Zealand Government sold off the commercial arm of
Radio New Zealand, which included, among other things, the ZM stations. The new owner was
The Radio Network, a subsidiary of
APN News & Media and
Clear Channel Communications, which operated as a division of the
Australian Radio Network. ZM made a return to the Auckland market in February 1997 as a local station broadcasting on 91.0 MHz as 91ZM. This move was made by The Radio Network after purchasing stations in Auckland and the Waikato previously owned by Prospect Media. TRN closed Auckland station
The Breeze on 91 and replaced this station with 91ZM. In Waikato
The Breeze on 89.8 was closed and replaced with a network feed of Auckland's 91ZM branded as 89.8ZM. The Waikato station did contain its own local breakfast show between 1998 and 1999. In 2000 ZM was consolidated into a single network feed with all programming on the networked ZM stations now originating from the 91ZM Auckland station. Between 2001 and 2014 the ZM breakfast show presented by
Polly Gillespie and
Grant Kereama was networked from Wellington to a nationwide audience including Auckland. In recent years the 10 am – 3 pm the announcer produced a localised show for Auckland with local voice breaks for Auckland listeners and then a generic voice break for the rest of New Zealand. As of 2013 all ZM stations contain the same content. ==Local programming==