The campaign to save the non-commercial TVNZ7 has not ended despite the channel's closure.
The Save TVNZ7 group lodged a complaint with the Ombudsman on Friday.
The free-to-air station ended transmission at midnight on June 30 and became a TV One Plus 1 channel, replying the same programmes but with an hour's delay.
The lobby group had signalled its intention to lodge a formal complaint after seeking advice from high-powered constitutional lawyer Mai Chen.
Save TVNZ7 spokesman Myles Thomas said the complaint hinged on TVNZ's failure to have regard for the public interest and to provide high quality content without the channel.
"On behalf of the 36,155 people who signed the online petition and the 1.6 million monthly viewers in TVNZ7's last month, we ask the Ombudsman to investigate a government decision that brought to an end NZ's last public service channel, severely limiting New Zealand's television options."
TVNZ had to close down the channel after the Government left it with little choice, he said.
"By doing so we believe they are neglecting their responsibilities to the public of New Zealand."
It also raised concerns about political influence in the decision, Thomas said.
The Government declined to put more money into TVNZ7 but told the state broadcaster it could fund the channel out of its own resources.
A spokeswoman for TVNZ has said the company did not see any issues but would cooperate with the ombudsman if necessary.
- © Fairfax NZ News
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