The Government was embroiled in a row with unions today after being accused of "bullying" civil servants to leave their jobs with reduced payouts.
The Cabinet Office announced yesterday that it had ended negotiations on a new scheme, covering all civil servants, setting out the level of compensation if they are made redundant.
Cabinet Office minister Francis Maude said five unions - Prospect, the FDA, Prison Officers' Association, Unite and GMB - had made "great efforts" to reach an agreement and were set to consult their members.
But the POA reacted with "fury", saying the Government was giving the impression that the unions had agreed to the new scheme.
POA general secretary Steve Gillan said: "I am absolutely appalled that Francis Maude has stated that the POA have reached these new terms with four other unions. He is misleading Parliament and the general public by his outrageous claims.
"The National Executive Committee of the POA is not due to meet until next Tuesday and it will only then be decided on our approach and response."
The POA said it is concerned that any ongoing discussions may have been deliberately "sabotaged" by the Cabinet Office.
Unite also made it clear there was no agreement, saying its officials will be telling its 22,000 members that the offer was the best that could be achieved through negotiation, but the terms would be worse than before.
The Public and Commercial Services union (PCS), which has already taken legal action over changes to the compensation scheme, said the new scheme is "unacceptable".
The union's executive demanded further negotiations with the Cabinet Office, warning it will ballot its members to reject the deal if talks are not successful.
The PCS also announced that it will go ahead with a challenge under the Human Rights Act to the current legislative attempts to cut redundancy pay.
General secretary Mark Serwotka said on BBC Radio 4's Today programme: "I hope the minister's going to apologise because yesterday his Cabinet Secretary wrote to the entire civil service saying all five unions had agreed.
"We now know that the second largest - the Prison Officers' Association - overnight has issued a very tough statement saying that's misleading, that they haven't agreed to this package whatsoever and that they're still discussing it.
"People are being misled in an attempt I think to bully them into thinking they have to go and they will go on reduced terms."
Mr Maude told the programme: "We have agreement with five unions, with the negotiators of five unions. There are two phases that then need to be gone through - first is agreement by their executives, which has happened in most cases, but I think the POA's executive doesn't meet until next week - which would then, we hope, result in a recommendation."
Asked to confirm whether it's "not a done deal", Mr Maude added: "It's agreed with their negotiators but I wouldn't want in any way to pre-empt the decision their executive makes."
The Government is pressing ahead with legislation to introduce new redundancy terms, through a Bill currently going through Parliament, adding that it wants to implement the new terms as soon as possible.
The Report Stage and Third Reading of the Superannuation Bill will be in the Commons on October 13.
Under the new scheme, civil servants would receive one month's salary for every year of service in the event of redundancy, capped at 12 months for compulsory redundancy and 21 months for voluntary redundancy.
All civil servants who are made redundant would be entitled to a three-month notice period.
Brian Strutton, national officer of the GMB union, said negotiations with the Government over a new compensation scheme had ended.
"We are going back to our members to consult with them and we are advising that these are the best terms we can get through negotiation."