Executives, senior staff and on-air talent are said to be furious with the company's embattled CEO, Mark Weldon, and are planning a series of individual actions.
"There is a threat of mass resignations across TV and radio, not just news," said a senior MediaWorks source. "If there are no actions by the board in the next 48 hours then resignations at the executive level - and throughout the rest of the company - are expected within days."
Weldon's brief but tumultuous tenure has already seen the loss of experienced staff, the end of Campbell Live and 3D, concerns over declining TV ratings and ad revenue, along with a steady stream of embarrassing news stories about the organisation.
While there have been rumblings from MediaWorks for a long time, Barry's resignation is seen by a number of key staff as a bridge too far.
A senior source says the problem is company-wide and not simply isolated to the newsroom.
"Company leaders are very anxious and unhappy about the way he handled Hilary's resignation," another senior MediaWorks figure says. "This feels like a tipping point."
The stage was set for an explosive board meeting, scheduled for today, featuring two new members who have recently joined the tight four-person board.
Company sources suggest staunch Weldon ally Rod McGeoch - who granted Weldon a controversial contract extension last year - is likely to step down as Chair, to be replaced by Jack Matthews, one of two recent appointments by MediaWorks owners' Oaktree Capital.
A number of senior staff were said to be waiting on the outcome of the meeting to determine their course of action. Anything short of Weldon's resignation will likely be viewed as an inadequate response to their concerns.
The losses of John Campbell and now Hilary Barry, who impacted everything from revenue to mentoring, have had flow-on effects throughout the business. They are emblematic of the large number of senior employees who have left the company since Weldon's appointment in August of 2014.
While Weldon cannot be held responsible for every departure, the seniority and sheer number of those who have left has troubled remaining staff.
Losses include Peter Crossan, Liz Fraser, Clare Bradley, Paul Maher, Katie Mills, Rachel Lorimer, Amanda Wilson, Mark Jennings and Inna Goikhman - key figures from areas as diverse as finance, revenue, legal, television, marketing, communications, news and research.
Ironically Weldon was allegedly critical of MediaWorks' legendarily low staff turnover on arrival: "There's not enough new blood," he reportedly told members of the executive.
Our sources allege that turnover has soared to between 20 and 30 per cent under his watch. This has led to retention and recruitment becoming a far more arduous and expensive task company-wide - a bitter blow for an organisation that was once the most coveted employer in the industry for on and off-air talent.
"The company can't afford to keep losing people because the reputational damage means you have to pay even more to replace them," a MediaWorks source said. "You're essentially paying them danger money."
The steady stream of negative news stories has been felt acutely within sales, and The Spinoff understands the most recent revenue figures are particularly troubling.
The already-difficult current media environment has been exacerbated by the erosion of the once-rock solid TV3 brand, and "there are concerns among the leadership about what advertisers must be making of all of this," says a senior management figure.
While radio and television have both suffered, no area has been as problematic as the new ventures Weldon has championed. Gossip site Scout was the subject of an embarrassing investigation by The Spinoff, and has had consistently poor audience figures.
The much-vaunted launch of an events division as a joint venture with Australia's Channel 9 has been similarly lacklustre, with little to show for its first year in business.
However, unlike television and radio, both Scout and events seem to be above criticism internally. "You bring them up at your peril," said a source privy to executive-level discussions.
The bungled handling of Barry's departure was allegedly the final straw for several senior company leaders. The presenter was the organisation's most well-liked star, and a beloved figure in the newsroom.
Despite that, many senior staff only learned of her departure hours before it was announced - after the news had leaked to Herald journalists Matt Nippert and Miriyana Alexander. To make matters worse, when Weldon finally informed staff, he misspelt her name in the email subject line:
Now, with Barry gone, there is huge concern she might tempt other media organisations to approach MediaWorks' remaining talent.
Internal fears abound that Paul Henry, who loved working with Barry, might follow her lead and resign. The Spinoff understands his contract is up toward the end of the year, and that he will likely be devastated by Barry's departure.
"Henry will be asking 'how could this have happened?'," and will demand an answer from Weldon, said a senior MediaWorks source, who characterised Henry as being "intensely loyal - not to corporates, but to the people he works with".
Other media companies, scenting blood in the water, might be emboldened to make a play for Henry or the statesmanlike anchor Mike McRoberts, who has lost both Barry and his wife, Paula Penfold, as colleagues within a matter of months. "It'll be open season on talent," said a source.
The loss of either Henry or McRoberts would be a further blow to the company's radio and television schedule, and create another empty shelf in its increasingly bare cupboard of stars.
This was the backdrop to today's board meeting, which was shaping as the most important of Weldon's MediaWorks career. It's a pinch point that has loomed for nearly a year now.
It's one he will have seen coming. Weldon has what was described to the The Spinoff as a suspicious nature. It wasn't always justified. "When he arrived, everybody did have an open mind," a MediaWorks insider said.
Now, the same source says, he's absolutely right to be paranoid - senior staff really are out to get him.