The Institute of Healthcare Management (IHM) is 'close to' calling for the withdrawal of the Health and Social Care Bill.
An IHM member opinion poll found managers had experienced "worsening conditions" for both patients and NHS staff thanks to the reforms.
The official release of the survey is not due until 14 February but Sue Hodgetts, Chief Executive of IHM, told MiP that 87% of its members that have responded to the poll currently want to see the bill withdrawn.
Hodgetts said that within minutes of the request being posted online, the IHM was able to "confidently" say Health and Social Care managers do not support the Health Bill and the "inevitable consequences" of it.
She said it is "very likely" the IHM will make an official call for the withdrawal of the bill next week.
IHM leaders criticised the government's almost "total disregard" for its advice given during its consultation period last year.
The claim comes following the news the Prime Minister David Cameron's former advisor James O'Shaughnessy told a Times reporter the bill's 'pause' period was nothing more than a 'sham'.
Professor Steve Field, chair of the NHS Future Forum, the independent group set up to lead the government's consultation exercise, vented his fury at the revelation on Twitter.
"I am furious - I was appointed to lead an independent group - independence guaranteed at first meeting with PM," he tweeted.
Hodgetts told MiP O'Shaughnessy's claims "make sense" as the government has made "no attempt" to implement any of the advice given by the IHM, despite lengthy talks.