Around 140,000 local authority jobs are expected to be axed in the next year because of spending cuts, council leaders have warned.
The Local Government Association had predicted that 100,000 posts would go across England and Wales after Chancellor George Osborne set out the broad framework for public spending in the June budget.
But the association said that the Government's decision to front load a large proportion of the cuts into the first year, rather than allow councils to spread them evenly over the four years of the spending review, was likely to lead to more jobs being lost.
The "unexpected severity" of the first-year cuts means councils will have to trim their budgets by an average of 11% in 2011/12, said the LGA.
Some authorities will also have to deal with the "difficult impact" of the loss of the Working Neighbourhoods Fund, which channelled £450 million to different parts of the country.
The LGA called on the Government to ease the effect of reductions in next month's local government finance settlement so that councils could spread the cuts more evenly over the next four years.
National officer Brian Strutton said: "Local government frontline services will be badly damaged by 140,000 job losses predicted by LGA for next year. The Tory/Liberal Government has taken an almighty gamble with people's livelihoods by cutting public spending instead of putting the priority on growth and getting the unemployed back to work. It is not possible to deflate the economy back to growth and a balanced budget."
A spokesman for the Communities and Local Government Department said: "The local government finance settlement is due shortly and will be announced in a statement to Parliament. We are not going to pre-empt that statement and any commentary ahead of formal publication is pure speculation and in this case scaremongering.
"We are working towards delivering a settlement that will help to protect frontline services and the LGA would be well placed to focus their efforts on working with councils to do the same."
A Whitehall source said the Government believed councils could protect frontline services, especially if they cut "non jobs" and tackled high salaries among senior officers.