Most of the Farm Terrace Allotment land will be used for health facilities and new homes, according Watford Borough Council.
The authority said 40 per cent of the 118-year-old site will be earmarked for the regeneration of Watford General Hospital as part of the health campus.
Borough officials also said the majority of residents who took part in a recent consultation expressed support for the redevelopment scheme, which promises to build around 700 homes and new hospital facilities behind Vicarage Road.
The council was responding to news that solicitors working on behalf of the Farm Terrace plot-holders had initiated judicial review against the Government’s decision allowing the allotment land to be used in the scheme.
The allotment-users are arguing the council "misled" Eric Pickles, the Secretary of State for Communities and Local Government, in its application for permission to build on the allotments.
Their case is the council’s justification for including the previously-protected allotments in the scheme was they are "critical to the viability of the development project".
However the allotment holders say the latest health campus masterplan shows the Farm Terrace land being largely used to provide parking for Watford FC and housing.
Following news of the judicial review, the council issued a statement saying: "We are disappointed by the news that the Farm Terrace Community Association is pursuing a judicial review of the Secretary of State's decision to include the Farm Terrace allotments in the Watford Health Campus scheme.
"Particularly in light of the fact that 77 per cent of people who took part in the recent Health Campus public consultation are backing the proposals
"We have clearly demonstrated why the inclusion of the allotments is in the wider public interest namely: the opportunity for new hospital facilities, much-needed affordable homes, 1,600 new jobs, accessible green and open spaces and better transport links
"The council and DCLG has rebutted all of the points made by the Farm Terrace Action Group in responses to their legal representative's pre-action letter."
The council said 333 people attended the recent public exhibitions on the health campus and 560 people completed its questionnaire.