Veteran news bosses believe there is still a chance TV3's news operations can be saved.
Owner Warner Bros Discovery on Wednesday announced plans to shut Newshub in June and a government bailout is off the cards.
Up to 300 people could lose their jobs.
The future of non-news programming is also under threat.
Journalists, commentators and some politicians said the closure was bad news for democracy and a forewarning of worse to come.
MPs shared their sympathies - and their concerns over the wider implications of one the country's major TV news services shutting down.
But Newsroom co-founder and former head of TV3 news Mark Jennings told Morning Report the key to Newshub's survival lay with its current owners.
He said staff should pitch massive cost cuts - including reducing the 6pm bulletin to 30 minutes with one presenter and getting rid of foreign correspondents.
"Chop out all the big-ticket items and then go to the big advertising agencies and the big companies in New Zealand and ask them to support Newshub with a bigger share of the advertising.
"Many of them would do it because they don't want TVNZ to monopolise that very important viewing sector and potentially jack the prices up."
Jennings said terrestrial television had about 10 years until it was turned off and broadcasters needed to innovate.
If Warner Bros didn't accept such a proposal they were clearly not interested in being in the New Zealand market, he said.
Media commentator Bill Ralston said while it would be a reduced news service, it would be cheaper.
"It's a real struggle to make a buck these days in television."
Ralston said there was "no hope" from the coalition government.
"(Broadcasting Minister Melissa Lee) is also constrained by her Cabinet colleagues, whose attitude to this financial collapse, essentially, of TV3 is 'oh dear how sad never mind'".
Associate finance minister David Seymour said while the government would not buy out Newshub, he had requested advice on whether government-owned TVNZ should start returning a dividend, to help level the playing field.
"I think there's a question mark around whether the government's ownership of one TV channel and the poor returns it's demanded as a shareholder has actually contributed to an uncompetitive market."
Government bailout unlikely
Broadcasting Minister Melissa Lee said it was something outlets around the globe were experiencing.
"I think journalists actually losing jobs - as a former journalist - I actually feel for them, I just think it's a sad day.
"Having said that, plurality is not an issue, because the way that people consume media has actually changed. We're no longer sitting in front of a television box watching the news at 6 o'clock.
Lee was given a heads up by network chief Glen Kyne on Tuesday night - before he broke it to the newsroom late on Wednesday morning.
She said Warner Brothers Discovery did not ask the government for financial assistance - and she was clear it cannot intervene.
And Labour's broadcasting spokesperson, the former minister, told Morning Report his party wouldn't have bailed Newshub out either.
"I think it's probably a bit much, you and I both know, anybody would know, you've got a $20m company behind Newshub," Willie Jackson told Morning Report.
"I know we would not have intervened, but we would not have just left them in the lurch."
He said they would have brought the company in and tried to help them find a way through.
Jackson questioned Lee's commitment to finding a solution.
He said Newshub briefed him about financial difficulties last year - but the closure was a surprise.
"They did say things were not going too well, they didn't ask for any assistance in terms of funding but they were pretty clear that things were not too good."
Sadness for staff and democracy
Broadcaster Mihingarangi Forbes told Morning Report there was a real need for public interest journalism but being a journalist in New Zealand was hard.
She said TV3 had a lean mean mentality and "has been a really good environment for Māori to grow".
New Zealand Broadcasting School tutor and former TV3 journalist Jeff Hampton said people were still watching "good, high-quality content", even if it was on their phone.
He said the government needed to tackle the threat of global companies such as Meta and Google, who used local news content without paying for it.
A bill passed under the former Labour government is currently before select committee on that issue.
But Hampton told Morning Report he would hate to see a return to the "bad old days" of only one television news channel.
Deputy Prime Minister Winston Peters framed the situation as a disaster for staff and New Zealand.
"A critical part of any democracy and free society is the fourth estate, an independent fourth estate, and I'm concerned about where we're going now," he said.
"Frankly for those 300 or so staff and their spouses and their families, this is an absolute disaster. But it's also a disaster for this country's democracy."
Deputy Labour leader Carmel Sepuloni told First Up the probable closure was sad and disappointing for those losing their jobs, and democracy.
"In this day and age when we're bombarded with information, some of which is not true, it's really important that we've got trusted sources of information and now we're not going to have that through Newshub."
She said while it was not always comfortable when journalists asked questions, they were "doing their job".
"Respect for the work they do and it's fundamental, like I said, for our democracy."