The purpose of a trust for council property is explained in a part of the law called section 225E. You can find this in the Local Government Act 1974. This section was repealed, which means it is no longer part of the law, on 1 July 2003, by section 266 of the Local Government Act 2002, which you can read more about at https://legislation.govt.nz/act/public/1986/0120/latest/link.aspx?id=DLM174092.