Plans to have volunteers working in Liverpool's museums as part of Prime Minster David Cameron's "big society" have been branded "hypocritical".
Mr Cameron cited National Museum Liverpool (NML)'s volunteer scheme as a good example of his proposals.
But former volunteer group Friends of NML (FNML) said it was treated "shabbily" before it disbanded in 2008.
Phil Redmond, NML chairman, said their current volunteer scheme was "totally different" from what FNML had to offer.
Liverpool is one of four areas taking on one of the "big society" plans.
Mr Cameron highlighted NML's use of volunteers, who are to be enlisted to help keep museums open for longer, as part of his community empowerment speech.
NML's venues include World Museum Liverpool, the Walker Art Gallery, the Merseyside Maritime Museum and the International Slavery Museum.
Andrew Pearce, who was chairman of the FNML when it disbanded, said: "How dare NML now call for volunteers when it treated the volunteers it previously had in such a shabby manner?
"Would it treat new volunteers any better than it treated the previous Friends?"
They claim that the museums' board suddenly decided to "cease contact with the voluntary group".
"Without the FNML, the maritime museum would not exist," Mr Pearce said.
He said it would be hypocritical for the NML board of trustees to call out for volunteers when they previously had 1,800 of them willing to give up their own time to help the museums.
Mr Redmond said: "We want volunteers who are more hands on on a daily basis, who will come in and help run the museums after five o'clock.
"At the moment our museums open for about seven hours a day - why shouldn't we extend this with the use of volunteers and have them open the museums at weekends?
"We train them up on health and safety and various other essential skills and they can help make a difference.
"It is not about replacing our staff - who I should not need to reassure because without them NML would not be where it is today. We just want make best use of the funding we receive from the government.
"And if they try and cut what we receive then I will be the first one fighting that."
Pete Middleman, regional secretary for the Public and Commercial Services Union (PCS), said the government's ideals of volunteerism and philanthropy were throwing the country back to Victorian times.
"We are anticipating losing 6,000 civil service posts across Merseyside when the government comes back with its spending review in October.
"That will include staff with the NML and the Tate. We are concerned this whole "big society" idea is a smoke screen for making a smaller state, cutting jobs and bringing in volunteers to fill the gaps."