If you want to conduct an activity on a site that it not provided for as a permitted activity you will need a land use consent. The District Plan contains specific rules for each zone outlining what can and cannot be done as a permitted activity.
In some instances the activity may be permitted, but the size and scale may lead to a non-compliance with a performance standard and therefore land use consent is also required. For example a house may be a permitted; however, if it exceeds the maximum height allowed in the zone a land use consent will be required.
In assessing whether your project requires a land use consent it is important to look at the applicable zone rules as well as the general rules.