One million new affordable homes are planned to be built by 2020
The number of planned affordable homes built over the next 10 years could be halved by government spending cuts, a housing campaign group has warned.
The government has promised three million new homes by 2020 - a third "affordable" below market rates.
The National Housing Federation said pre-Budget report figures suggested the housing budget could be cut by 17.98%.
Housing minister John Healey said the government had demonstrated a long-term commitment to affordable housing.
The National Housing Federation (NHF) warned 556,000 affordable homes - which are categorised as more expensive than council properties but priced below market rates - would not be built, affecting 278,000 jobs.
It said 1.25 million people would join the record 4.5 million people on waiting lists for affordable housing if the target of one million homes was not met by 2020.
The federation called for housing budgets to be protected in similar fashion to services such as health and education.
Chief executive David Orr said: "A swingeing cut of 17.98% to the budget for new affordable homes would deepen the national housing crisis and lead to the loss of thousands of jobs and apprenticeships.
"Reducing the number of new homes by such a huge degree would kill off the dreams of more than a million people in desperate need of decent, affordable housing, leaving many to live in cramped, unsuitable conditions for a generation.
"As bad housing is closely linked to poor health, poor educational attainment and higher crime rates, ministers should give funding for the house building programme the same untouchable status as health, education and policing, and protect it from the coming savage cuts."
'Support for buyers'
Mr Healey said while the NHF was right to lobby government, it was in danger of "missing the bigger political picture".
"Of course the public finances are tight but this government continues to demonstrate our long-term commitment to affordable housing, whether through the extra £1.5bn investment of the Housing Pledge or the pre-Budget report's boosting of support for first-time buyers," he said.
"The Tories not only opposed us, they also proposed a £1bn cut in last year's housing budget that would have seen 9,000 fewer homes built and the loss of many jobs in the construction industry.
"Taking this as a clear indication of Tory priorities, the NHF would do well to consider the threat a Cameron government would pose to affordable housing," he said.
Shadow housing minister Grant Shapps said no previous government had a worse record of affordable house building than "this fag-end Labour administration".
"As a result there are nearly twice as many families languishing on the social housing waiting list than when Labour came to power," he said.
"With this appalling housing record, no one should take lectures from Labour housing ministers who seem to come and go faster than most people have hot dinners," he said.
The NHF based its figures on analysis of the pre-Budget report by the Institute for Fiscal Studies.