Councils will need to "exhaust all options" to meet strict new homes targets set by the Government, the housing minister warned on Thursday.
Matthew Pennycook said local authorities that had exhausted brownfield land for building would need to look at “low-value” greenbelt sites for housing.
He added that the Government is “absolutely willing” to step in and take a local plan away from councils that fail to meet homebuilding targets.
The Prime Minister and his deputy Angela Rayner have pledged to build 1.5 million homes over the next five years and take decisions on 150 major infrastructure projects this parliament.
Sir Keir Starmer has also promised to "overhaul the broken planning system" in a bid to get more people on the housing ladder.
Mr Pennycook told Times Radio: "We know those targets are stretching in many parts of the country, and what I say to local authority leaders is just 'exhaust all your options to meet those targets', whether that be bringing forward brownfield, previously developed land, densifying that land, looking to release, say, poor quality grey belt land within the green belt - if you have any - through green belt reviews."
The updated national planning policy framework (NPPF) will commit to a "brownfield first" strategy, with disused sites that have already been developed in the past prioritised for new building.
When a developer seeks to build on brownfield sites the default answer will be "yes".
But town halls will also be ordered to review their green belt boundaries to meet targets by identifying lower quality "grey belt" land that could be built on.
The definition of grey belt put forward by the Government is "land making a limited contribution to the green belt's purposes", Mr Pennycook said.
He told BBC Radio 4's Today programme: "Essentially, what we're trying to get at with grey belt is the fact that the green belt itself isn't an ecological designation, and we know there are lots of parcels of land within the green belt that are poorly performing against its purposes.
"They might be previously developed sites, disused car parks, abandoned petrol stations. They might just be really poorly performing scrub land in certain circumstances.
"And what we're saying is there's got to be a smarter and more strategic way to look at green belt release.
"It happens very often. It's happened for the past 14 years but in a haphazard way... we want a smarter and more strategic way to release the right parts of the green belt where that is required to meet local housing need."
However, shadow housing minister Kevin Hollinrake said Labour's housing plans would amount to "bulldozing" green belt sites and argued more homes should be built in cities like London instead.
He told Sky News: "We're not against building more homes. So we agree with those parts of the plan.
“What we disagree with is bulldozing greenfield, green belt sites. That's what we'll see. We'll see many of these homes delivered in rural areas, yet a lowering of targets in urban areas, particularly London."
