Efforts to improve the county's troubled children's services department could be hampered because of proposed council cuts which could have a 'devastating' effect, union leaders have warned.

And organisations which represent older people and the disabled have also criticised proposals in the £140m savings package unveiled by Norfolk County Council, saying they will lead to vulnerable people becoming isolated in their homes.

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The cuts have been proposed by the controlling Labour/Liberal Democrat administration at County Hall to help plug a £189m funding gap at the council.

The council says the gap has been created by a £91m cut in the amount of money it gets from the government, against a backdrop of increased public demand on services.

Social care for older people, transport for students, mobile libraries, school crossing patrols and help for people just out of hospital are all in the firing line, while the axe is also hanging over more than 500 county council jobs.

Next year will see council 260 jobs axed, with a further 260 the following year. A similar number could follow in the third year, but has yet to be confirmed.

Union UNISON, which represents council workers, said further cuts, on top of £140m over the past years which saw 1,600 jobs lost, would demoralise staff.

Although the council says it is pumping £16.5m into its children's services department in the wake of criticism from Ofsted inspectors, the union fears any good work could be undone by proposed cuts.

Among the cuts proposed are to save £17.6m by reducing the number of children in care by more than 770, but UNISON representatives are not convinced that will happen.

David Lambert, UNISON senior steward in children's services, said: 'Although the county council recently announced that there will be significant extra resources in social care following poor Ofsted reports, our members are worried the proposed cuts could make it more difficult to improve the services we provide.

'Children's services will have to save in excess of £30m over the next three years and this will mean cuts to rural transport subsidy, post 16 transport, school crossing patrols and school support.

'This will be devastating for many of those who rely on these services as well as our members who work in these areas.

'We note that the most significant proposal is to reduce the cost of funding for looked after children by over £17m over three years.

'This means that the county council will have to reduce the number of looked after children considerably.

'Our members are concerned because attempts have been made to do this in the past without much success.

Unfortunately these figures are often influenced by external factors such as the tragic death of Baby P, when the number of looked after children increased across the country and we are concerned that another tragedy could hinder this plan.'

Steve Morphew, cabinet member for finance, said: 'We are looking for savings in children's services, but that should come from the investment we are making. One of the most expensive things we do is look after children.

'By trying to intervene earlier that will improve the quality of the kid's lives and mean they do not have to come into care.'

And UNISON also questioned proposed cuts such as one to save £12m over three years by limiting what people can spend their personal budgets on, so they would not be able to use them on wellbeing activities - such as going to the cinema.

The council's hope is that voluntary groups would help provide wellbeing activities. But Alison Birmingham, UNISON's senior steward for adult social care, warned that the proposal, along with another one to make some people pay for transport to day services, could increase isolation.

She said: 'UNISON members and citizens will feel let down by this budget, as it takes away some of the vital measures they have come to rely on. They do need to understand this is something forced on the council by government policy.

'For our members, it is unclear how they will manage rights and expectations in social care with vulnerable people – especially when cuts through other agencies are beginning to have an effect too.

'All the current talk in the NHS and adult social care is around reducing dependency and promoting independence but this takes investment, not cuts.'

Phil Wells, chief executive of Age UK Norwich, said he understood that government cuts were forcing the council's hand, but that, with about £24m of cuts likely to directly impact on older people it was a huge setback. He said: 'What they are doing is cutting out anything which they do not have a statutory duty to provide. It's keeping people alive, but not keeping people well.

'It is going to put the responsibility on the community to support people with moderate needs, such as those who are lonely who cannot get out and about.

'We can't pick it up as we don't get the funding. The only way we can do it is by people working with us, which is something we have been working hard to do already.'

Another of the proposals, to save £6m over three years, is to reorganise how care is provided to people with physical or learning disabilities.

Between April 2012 and March 2013, the council provided support for 2,062 people aged 18 to 64 with learning disabilities and 1,847 in the same age bracket with physical disabilities.

The council acknowledges its proposals, which may mean changing services or re-negotiating contracts with providers, could lead to some people no longer getting care 24 hours a day, seven days a week.

Equal Lives, an organisation which supports disabled people in Norfolk, raised concerns about that and the changes to the personal budgets.

Chief executive Mark Harrison said: 'Disabled people have been targeted in a disproportionate and discriminatory way by the coalition government's austerity programme.

'We were promised in the Big Conversation that this would be the end of it, now they are proposing to take out even more over the next three years.

'If these cuts got through then many disabled people will become 'prisoners' in their own homes. If you cut people's personal budgets back to just receiving personal care, which for many is what is being proposed, then people will not be able to go out.'

The proposals, which would save £140m over the next three years as the council looks to plug a £189m funding gap, have been revealed as the county council calls on the public to have their say in a consultation called Putting People First.

People can see the proposals and have their say by visiting www.norfolk.gov.uk/puttingpeoplefirst, while hard copies are available by calling 0344 800 8020.