The board met this week to discuss the idea, which it described as "a mature examination of green belt principles to see whether and how they can evolve to fit 21st century circumstances".
It insisted that any review will not be done in a way that provokes claims of "concreting over the countryside". It will look at fresh ways of greening development and improving underused or neglected green belt land.
Natural England chairman Sir Martin Doughty noted: "We need a housing solution that creates a network of green gaps and corridors."
An RTPI spokesman said: "Natural England is putting forward a case that we have been making for many years. Evidence clearly shows we must review the green belt."
- Housing Growth and Green Infrastructure is available at PlanningResource.co.uk/doc.