A group opposed to the axing of TVNZ7 is to lodge a complaint against TVNZ with the Ombudsman.
The station was switched off at midnight on Saturday.
Save TVNZ7 spokesperson Myles Thomas says the State broadcaster has neglected its legal duty to consider public interest when deciding programme content.
He says the group has received legal advice which indicates TVNZ has a case to answer.
The group hopes to lodge the complaint this week.
New public service TV channel proposed
Plans are afoot to resurrect a public service television channel following the shut-down of TVNZ7.
About 400 fans of TVNZ7 attended a rally in Auckland on Saturday night to mark the demise of the non-commercial channel.
They were told different groups are working on plans to bring public interest television back to people's screens.
David Beatson, who has worked in the media and public relations, said he wants to set up a new channel showing public interest programming.
He said he's aware of the cost and the challenges, but still wants to try.
"If the Government won't or can't do it, then maybe the people will. So we've got to get out there with a model, which I think is workable, and just test the water and try as fast as we can to fill the void that 7 will leave".
Mr Beatson said the channel would operate through a non-profit organisation and he is in the process of developing a trust deed.
Labour Party broadcasting spokesperson Clare Curran said the party would be proposing the creation of a new public service channel at the 2014 election.