The function of each of the nine centers under the IAVW is to respond to reports of volcanic ash within their region and provide forecasts to the aviation community of ash cloud extent and movement. Observations may come from ground stations and Volcano observatories, aircraft in flight or orbiting satellites. The ash warnings issued are in the form of Volcanic Ash Advisories and SIGMETs describing the current and future extent of ash.

Volcanic ash constitutes a serious threat to aircraft operations primarily due to the effect of the corrosive gases and abrasive particles on aircraft engines and airframe. In addition to loss of engine performance or even flameout, ash effects may include instrument and radio failure, visibility problems and damage to other external flying components as well as contamination of the aircraft interior.

Such potentially serious and expensive damage is best prevented by avoiding flying through ash altogether. Over recent years, improvements in observation networks, satellite technology, computer modelling and our increased understanding of the phenomena have led to improved volcanic ash forecasting methods.

The Wellington VAAC is operated by Meteorological Service of New Zealand Ltd (MetService) on behalf of the Civil Aviation Authority of New Zealand (CAA NZ), which is the New Zealand Meteorological Authority.

The Wellington Volcanic Ash Advisory Centre area of responsibility covers an area southward from the Equator to the South Pole between 160E to 140W and southward of 10S between 140W and 90W.