St Helier's green spaces will be excluded from any potential future site list for Jersey's new hospital.
Constable Simon Crowcroft's amendment was approved in the States Assembly by 24-22.
It means that if Gloucester Street is removed as the chosen site, the new hospital will NOT be built on People's Park, Lower Park, Victoria Park, Westmount Gardens or Parade Gardens.
Politicians will now decide whether to rescind the previous government's decision to build the new hospital on the current site, after two attempts at planning permission were rejected.
Constable Crowcroft says People's Park should never have been in the running.
"I've never denied that it's (People's Park) the best site for the hospital, but it isn't available, because it's a park.
"There is no point in leaving these spaces on the table. Let's look at the other sites (if Deputy Russell Labey's proposition is approved) without distraction."
The Assembly has also backed Deputy Kirsten Morel's amendment to start any site selection process from scratch, if the Gloucester Street site is scrapped.
Haut Du Mont trial: Worker told colleague he 'didn't test' gas main
Shear relief for Romerils as Shaun the Sheep found!
Electricity companies sign four-year deal with EDF
Filming underway for Bergerac Series 3
Teenagers wanted to join Jersey Youth Assembly
Jersey Bulls knocked out of FA Cup
Residence and employment rules simplified
RNLI Jersey back on Saving Lives at Sea
