Council leaders and developers have written to local government secretary Michael Gove criticising the Government's proposed infrastructure levy.
They said the proposed reform, which would allow councils to impose a levy on developers based on the estimated final value of a scheme, could mean fewer affordable homes being built, and less money for roads, health centres and schools.
In the letter, the County Councils' Network, District Councils' Network (DCN) and 28 other organisations called instead for reform of the developer contributions system.
The DCN described the Government's existing plan as 'unworkable'.
It warned the levy, which is intended to increase the number of affordable houses built and the amount of infrastructure supplied for new developments, was likely to have the opposite effect and would 'heap financial risk on local government'.
DCN's Barry Wood said: 'While we support the principle of local planning authorities being allowed to borrow against the proceeds from the infrastructure levy what has been proposed would [place] significant financial risk on councils.'
