Nelson Street car park and the old fire station in St Helier will be 'safeguarded' for a new youth centre.
If another site is found for it, then Nelson Street will stay as it is.
Deputy Rob Ward won a States vote in December 2018 for 'purpose-built youth facilities' in the north of town. No location for it has been indentified since.
£4.25 million was set aside for the project.
The Brewery site is one of a few other options to be considered for the centre.
Springfield and the old Jersey Gas showroom have also been considered.
Deputy Ward says St Helier desperately needs such a facility in the north of town, especially with the additional homes being built.
"Young people have to have somewhere to go. It's no good to complain about young people's behaviour and saying they're wandering the streets in groups and they're making a noise.
Young people do tend to be a bit noisy. That's because they're doing and vibrant and that's OK.
What the youth service do is provide opportunity and activities and support and direction for young people in an astounding way on this island.
What they need in the north of St Helier is a state of the art facility to do that in. The money is there, we just need the site.
What I'm saying is if we rezone this and have it as a back-up site if the Brewery site doesn't work and the plans are there and the money is there, then it gives us the opportunity to actually produce this facility.
This amendment is a simple one. It says we're going to protect this area as a fall-back and it's basically saying to us 'get on with it'.
You've talked enough, you've agreed enough, but now get on with it."
The Constable of St Helier opposed the plans because of concerns about parking and the St Helier Honorary Police.
St Helier parish hall enquiries take place in the old fire station in Nelson Street car park.
35 car park spaces would be lost if a youth centre is built there.
Constable Simon Crowcroft says the Honorary Police don't want to leave their home - and he was disappointed to see Deputy Ward's proposal as a result.
"Before one takes a proposition to the States Assembly which could affect ones Honorary Police force, one at the very least, I think, would hold a Parish Assembly to make sure that these matters are fully aired and that the feedback of Honorary Officers is fully heard.
I think that's particularly important as we come out of a pandemic in which St Helier's Honorary Police has, by all accounts, performed incredibly well and I know four St Helier Centeniers in particular have taken onboard the charging for the whole island during the pandemic while other officers have done an enormous amount of work, unpaid of course, out in the community at anti-social hours.
So my concern about this proposition is that it doesn't send a very good message to the St Helier Honorary Police that the States Assembly is saying well, if there's nowhere else, we'll potentially take their building away from them.
Local residents have lost a lot of parking facilities and the ones (parking spaces) that are coming on stream at Ann Court will merely replace the ones that were on that site before the development by Andium Homes took place.
I think St Helier can ill-afford to lose these spaces for locals but also for shoppers, for visitors, people going to the town park, people attending the St Helier Honorary Police parish enquiries.
I would expect a very strong opposition indeed from St Helier residents at the idea that they might lose Nelson Street car park was to be endorsed in the Island Plan."
Deputy Montfort Tadier says he signed a pledge to put a children first, not one to put the St Helier Honorary Police first.
His Reform Jersey colleague Senator Sam Mezec says Deputy's Ward's proposal was 'borne out of frustration'.
He thinks the Nelson Street car park can be lost because of the new spaces coming underneath Ann Court.
"That was one part of the benefit of the Ann Court proposals was that there were going to be a significant number of parking spaces delivered there, so people will be able to park their cars just a short distance from that site and it's a much greater number than those that could theoretically be lost at Nelson Street.
There are other ways which you can find facilities for the Honorary Police in St Helier. The Constable says he's spoke to them and they were very clearly against moving. Well of course they would be. Why would they want to move unless it was necessary? If that becomes the necessary option, well that will just be the democratic process.
I actually don't share the Constable's assumption that if this were proposed there would be some mass unrest in St Helier over it, I think he's misjudging people's appetite there. I don't really think that many people in the community that I'm a resident of would be so opposed to having parish hall enquiries actually held at the parish hall.
I think many would be extremely pleased to see a youth and community provision provided there, because the people who live in that area know how desperately it's needed and can often see, as they're walking around the area, how bored many of the young people often are and at a loose end rather than benefiting from youth service provision which is what they could be doing.
This doesn't tie our hands to providing this facility on the Nelson Street site, but it just leaves it open in case we need it. What's the problem? Sounds alright to me."
Deputy Ward's amendment to the Bridging Island Plan was approved by 33 votes to 10.