Details on the media mega-merger between TVNZ and RNZ have been revealed before the official announcement at noon tomorrow. 

Sources have told the Herald that Cabinet has signed off a plan that would see both organisations dis-established to create a new entity. 

Under this new structure, RNZ properties would remain commercial-free, while TVNZ would still have some commercial imperatives but would not be required to pay a dividend to the Government. 

It's understood that the new entity will be based on a not-for-profit model. 

As a general rule, the public interest emphasis will override the commercial imperative within the firm. 

A source close to the matter stressed to the Herald that dis-establishing the corporate structure didn't imply that TVNZ and RNZ would simply disappear. It's understood the viewer and listener experience will remain largely unchanged over the prolonged transition period. 

The Herald understands that the Ministry of Culture and Heritage is working through the details, including how the news operation would operate across the two newsrooms. 

Sources were still unclear on the extent to which the newsrooms would be merged to deliver both television and radio. 

The timeline of the proposed merger is also still unclear at this stage, but a document posted to the Ministry of Culture and Heritage website last year suggested the entity would be up and running sometime in 2023. 

It's understood that this plan remains in place and that TVNZ and RNZ will continue to operate in their usual form over the course of the transition period. 

Now that Cabinet has signed off on the plan to proceed, the focus will shift to drafting legislation to form the new public committee. A select committee will then review the draft legislation in the coming months, providing an opportunity for submissions to be made by any interested parties. 

Once the legislation is drafted, the focus will shift into the phase of integrating the entities to have the organisation fully operational in 2023. 

The governance group formed last year and chaired by former New Zealand First Minister Tracey Martin will work with the Ministry of Culture and Heritage on establishing the new entity. 

The Government has thus far kept its cards close to its chest with regard to the details of the merger but has made no secret of its intentions. 

In recent comments made to the Herald, former TVNZ boss Kevin Kenrick said that what the media sector needs right now is certainty on what the course of action will be and what the proposed restructure of the entities might look like. 

The responsibility of managing the transition from the TVNZ perspective will now rest with new CEO Simon Power, a former National Cabinet minister. 

The National Party has long been opposed to the merger, with former Opposition leader Simon Bridges going as far as saying he would torpedo any Government plan to merge RNZ and TVNZ. 

Doing so could prove challenging for new National leader Christopher Luxon, given that the merger process may well be complete by the time the 2023 general election is contested. 

Speaking to the Herald today, Luxon said National is still opposed to the RNZ-TVNZ merger but wouldn't commit to reversing it. 

"The TVNZ-RNZ merger is just not worth it," he said. 

"I think the Government is just trying to mash together two irregular jigsaw puzzle pieces. 

"You're mixing together two very different beasts in many ways. I think we're much richer for them telling their individual stories of New Zealand to New Zealanders." 

Luxon called the process "a bit of a mockery" and said that it was a "forced fit". 

"When you look for mergers and acquisitions - and I've done a lot of them in my life - what you're looking for is natural synergies and chemistry and alignment and to put RNZ together with TVNZ doesn't make any sense in my mind. 

"These guys [the Government] take an awfully long time, as we've seen with Three Waters, to do anything." 

Luxon said he first wants to see what the Government does before making a call on his plans to undo anything. 

"Let's just cross that bridge when it comes to it and see where we are." 

Minister for Broadcasting and Media Kris Faafoi will host a standup tomorrow at noon to reveal further details on the future of public media in this country. 

- Additional reporting from Wellington by Claire Trevett and Thomas Coughlan.