Nurses in the South West say they are being "driven" towards a "devastating and divisive" strike under NHS plans for regional wage deals by a so-called pay cartel.
Members of the Royal College of Nursing (RCN) have told the former Labour health secretary they feel threatened and fearful of speaking out against the proposals.
After a meeting in Exeter, MP Andy Burnham said he was "concerned" about the tactics of NHS employers involved in the cartel.
"People are really worried and fearful and many people don't feel able to speak out.
"But that doesn't mean they are not terrified about what it means for their jobs, homes and children."
Mr Burnham said he had "concerns" about the way members of the so-called cartel had gone about things... "issuing a paper that basically says if they don't agree with the terms then they won't be employed". He added: "It's a terrible way to treat the NHS staff who we were celebrating during the Olympic Games."
A total of 20 NHS organisations have joined the South West Pay Consortium (SWC) which aims to examine future financial challenges.
This has now reduced by one after the Bournemouth and Christchurch NHS Foundation Trust withdrew this week. The group aims to review terms and conditions, including pay rates, number of working hours, amount of annual leave and sickness leave entitlement.
The SWC, which includes hospitals in Exeter, Taunton and Plymouth as well as other NHS trusts, has not released any firm proposals as yet.
But unions from across the health spectrum have condemned the thrust of the SWC's work, saying it is an excuse to ditch hard-fought pay agreements and drive down pay and conditions.
Mr Burnham said cartel members "don't understand the value of what they have already got".
"Most people are already working more than their contracted hours per week and they have alienated them at a stroke," he added.
"Politicians weren't aware of the strength of feeling or how serious the cartel was but it is now on the national agenda."
Debra Nicholson, an infection control nurse, said they had been "banging their heads against a brick wall".
"People are being threatened by chief executives, messages coming out saying you mustn't talk to people about this and they are very secretive about board meetings," she added.
"Nurses are terrified and think they are going to lose their jobs and their income."
Asked whether the RCN members might walk out, another member Lors Allford added: "It would be a really sad moment for nursing but we don't know what else to do and their hands are tied.
"For some it is the last thing they want to do but they are being driven down a path where that might be an option – but it would be a devastating time and very divisive."