Affordable house building levels could plunge by 65% under the new coalition government, according to the National Housing Federation.
The NHF, which represents the UK's housing associations, predicted the number of affordable homes built this year may drop to just 20,390.
It added that the private sector would also be affected by the new government's plans, with the total number of new houses constructed likely to be less than 100,000 for the first time in almost a century.
This is just 40% of the previous government's target of building 250,000 homes each year.
The NHF's warnings follow heavy cuts announced by the Homes and Communities Agency, plus the scrapping of regional house-building targets.
According to the Observer, the federation's chief executive David Orr has written to housing minister Grant Shapps outlining his fears, stating: "If the government fails quickly to replace the regional planning mechanism it has just scrapped, the building of affordable homes could potentially grind to a halt this year – with all house building… falling off a cliff."
However, Shapps responded: "Houses cannot be built by targets that don't work with money that doesn't exist. We have the lowest peacetime rate of housebuilding since 1924 and top-down control that alienates the public and undermines support for new housing."