Cheryl Hague, of the Save S13 Green Belt group, said: “Since the Local Plan was first put forward, thousands of residents said the council should pursue brownfield sites and not the green belt.
“The council told us there were no brownfield sites left, but this request by the planning inspector certainly seems to contradict that.
“This just goes to show we were not listened to from the beginning by the council.
“This Local Plan is completely unfair, with S13 looking to lose almost all its green belt while more affluent areas of Sheffield are unscathed.
“We are not against house-building, we are against destroying the green belt when other more appropriate sites are available.”
Sheffield Council said the Local Plan would help provide more affordable housing, regenerate derelict land, create new jobs, improve public transport and reduce carbon emissions.
Labour council leader Fran Belbin has said she will meet campaigners at the weekend.
She said: “We will assess these six brownfield sites as requested by the Planning Inspectorate.
“However, any additional capacity on these sites will almost certainly be included in the Plan’s windfall allowance, which exists to account for sites that may become available over the course of the Plan.
She added: “There remains a real risk that rejecting the Plan would lead to a new, higher housing target being imposed that would require the inclusion of even more green belt land.”
The Liberal Democrats, who are in opposition on the council, said Labour and the Green Party had pushed ahead, paying little heed to any objections.
Lib Dem Ian Horner said: “This confirms what the Lib Dems have been saying for several months – the council failed to carry out a detailed investigation on a large number of sites, preferring instead to focus building over the green belt.
“Sadly Labour and the Greens decided to push ahead with it in the face of massive public opposition.”
Inspectors say a further set of public consultations on the latest modifications should run for at least six weeks.
The Green Party has been approached for comment.
