If you are considering building or plumbing work, you need to talk to Council to see whether a building consent is required or not.
Work that does require a building consent is set out by the Building Act 2004 (Schedule 1). Although your particular project may be exempt from the need for a building consent, the work must still satisfy the provisions of the Building Code.
Basic building jobs, such as laying a patio or installing kitchen cupboards, do not require a building consent.
On 1 March 2012, Restricted Building Work and Licensing came into effect. Building practitioners need to demonstrate their ability to meet industry competencies in order to obtain the status of a Licensed Building Practitioner (LBP).
Restricted Building Work is work which is critical to the integrity of a building and can only be carried out or supervised by LBPs.
For more information visit the Ministry of Business, Innovation & Employment (external link)
The website allows you to search the public register for LBPs in your area.