You will not be entitled to possessory title unless your occupation of the land is "adverse" to the title of the registered owner. Accordingly you cannot expect to obtain possessory title of land that you have leased or occupied pursuant to some arrangement with the registered owner. Any break in your possession of the land whether caused by the registered owner or any other party will mean that the 12 year period must recommence.
Application for possessory title is made by lodging appropriate documentation with the Department of Lands. This must include statutory declarations by a number of disinterested persons who are required to swear to the various facts on which you seek to rely to establish your right to possessory title.
Your application must be accompanied by a letter from the local council stating various facts as well as a survey of the land by a registered surveyor. Often land that is subject to an application for possessory title is land which has been overlooked by executors of a deceased estate. Accordingly your application must include probate searches identifying those persons entitled to be registered proprietors of the land but for your possessory title.
A grant of possessory title in your favour will be regarded as a dutiable transaction for the purpose of stamp duty. Accordingly it will be necessary to arrange for a valuer to determine the dutiable value of the land. Stamp duty must be paid to the Office of State Revenue at the normal "property transfer rates".
The Department of Lands is required to give the owners of neighbouring land notice of your application for possessory title. The notice period is 35 days however this can be waived if you can obtain letters from your neighbours consenting to your application. It is generally recommended that as soon as you form the view that you are entitled to possessory title to land you should lodge a caveat while preparing your application.