If you can find the location on the map in this brochure (I couldn't), you should be able to search online for the appropriate Victorian land classification and the regulations pertaining to it:
Nature Conservation Reserves are fine to detect in, however, some are subject to leasehold. There will usually be a sign on the fence line stating this.
If you wish to find out about any particular area contact Parks Victoria. Robert will help you to find out if there is any reason you cannot access a particular area. Nice bloke and very helpful.