The function of the Registrar-General of Land is to provide a system, whereby the ownership of land can be legally evidenced, under which dealings with it can be effected and recorded.

From the earliest days of colonisation, offices have existed in New Zealand for the registration of instruments affecting land. To enable a record of ownership of land to be kept the Land Registration Ordinance was passed by the Legislative Council of New Zealand on 28th December 1841. This provided for the setting up of Deeds Registry Offices and prescribed the method of registering Crown Grants and other Private Deeds relating to Land. The system is generally known as Deeds Registration System or Deeds System for short.

The Deeds System with modifications continued until the Land Registry Act 1860 was promulgated. After a number of amendments it was replaced by the Land Transfer System (LT Act 1870 and subsequent acts). This is sometimes called the Torrens System, after its originator in South Australia. Since the 1870 all registration takes place under the Land Transfer System. The Land Transfer System provides a simple method of registration and in addition, titles issued under it are guaranteed by the State. The first digital data was created by the Land Titles Office (a division of the Justice Department) in the late 1980s - early 90s. This data formed the electronic land transfer journal and a titles index (Land Title Link). The LTO was amalgamated with DOSLI and finally LINZ. As Landonline was rolled out, the paper titles were converted into digital computer registers. The titles conversion project converted 1.8 million "live" titles and imaged 2 million instruments. Certificate of Titles as they were previously known are now mostly obsolete as Computer Registers have been issued to replace them.

Prior to Landonline LINZ wrote memorials on the back of certain documents e.g. Gazette Notices and certain Leases. Because documents are now stored electronically Computer Interest Registers are now issued as the means for recording memorials affecting these instruments. Every Computer Interest Register relates to a specific document.