The requirement, which will undergo consultation "shortly", is likely to force councils to scrap affordable housing obligations to get stalled schemes moving, the NHF said.
The housing strategy, which Mr Cameron described as a "radical" way to "get Britain building again", estimates that there are 82,000 homes in stalled schemes across England which would benefit from renegotiation with developers.
Of the 82,000 homes in stalled developments, 16,000 would have been affordable homes imposed by a section 106 agreement, according to the NHF. A planning expert said that because affordable housing contributions are often more onerous than other planning conditions, developers are likely to want to slash them first.
"We are very concerned that ... there seems to be a trend of some local authorities allowing private developers to drop section 106 affordable housing deals too easily," said Cameron Watt, head of neighbourhoods at the NHF.
"The government should make it clear that there are some planning standards, including certain affordable housing requirements, that should not automatically be waived as a consequence of viability concerns," Watt said.
Development without any affordable housing should be unacceptable, the NHF said. They further submit that if section 106 agreements are to be revised on the basis of viability arguments, then the viability analysis should be available, in public, for all parties to examine.
