Government intervention and public outcry last month led the public broadcaster to shelve plans to automate Concert after a separate frequency was found for the proposed multimedia youth service.
The plan announced last month would have seen RNZ Concert taken off FM frequencies by May 29, eliminating 17 jobs including all presenter roles.
Those would be replaced with 13 jobs at the new youth platform, while four would have remained in the downsized RNZ Concert service and RNZ Music in Wellington.
RNZ management published the music strategy documents after requests under the Official Information Act.
A presentation to the board in October last year said although the audience size would be the same, about 160,000, the new station would represent a net increase in RNZ's reach, because most of its users would not already be RNZ listeners.
The proposal for "RNZ Music v 2.0" was framed as an opportunity to grow RNZ's audience in 18- to 35-year-olds, potentially adding another 127,000 listeners.
The documents showed this was seen as essential in achieving the goal of reaching "1 in 2 New Zealanders" by 2023.
A business case from December assessed the risk of a negative response from "audience and stakeholders" to the plan as "high."
To counter a negative response from the music industry, it raised the prospect of finding a prominent music industry personality to support it and possibly write an "op ed".
The papers revealed a launch date of August 2020, with plans to create 13 new roles including presenters drawn from the same audience the station would appeal to.
After the plan to automate Concert was withdrawn, RNZ chief executive Paul Thompson said RNZ would develop a new strategy for Concert aimed at improving its audience, while also working with the Government on the new service for young people.
However, the costings for the plans to maintain the former and push ahead with a new station have remained unclear, even as the Government pushes ahead with its plan to disestablish RNZ and TVNZ in favour of building a new public broadcasting entity.
