The embankment area will be painted with special temporary turf paint which lasts about three to four weeks and will display each of the six traditional and symbolic pride colours.
Wellington Mayor Justin Lester is delighted with the rainbow.
"Wellington is one of the most inclusive cities on the planet and we want to show our pride at holding the ILGA World Conference.
"Last year we painted the Rainbow Crossing on Dixon Street – it's not quite as big – to show how we embrace everyone. The airport rainbow will be the first many ILGA attendees see and I am sure it will make them feel welcome."
Co-chair of the Wellington Pride Festival Roxy Coevers said "to my knowledge it's the largest-scale painted rainbow in honour of pride in New Zealand, and the festival team is excited to have this very powerful and visual display of solidarity for LGBTQIAF+ folks during our yearly celebrations.
"We are looking forward to celebrating the festival with Wellingtonians and visitors alike, as well as the ILGA delegates and have put together the largest festival to date with over 128 events."
Painting the rainbow took around three days to complete and a time-lapse video was created to capture the painting process. The rainbow is visible from the embankment facing Cobham Drive.