"The Western Springs 'activation', as we call it, required the moving in of a whole lot of gear, so effectively we're moving that gear, instead of into one park we're moving it into another," he said on Radio New Zealand this morning.
"It is a lot of work, but we're also conscious that a huge amount of planning has gone into this, people in the Pacific Island communities have geared up for this, so we believed it was better not to delay the festival - and there was no certainty as to when we would be able to get access to Western Springs Park in the future.
"So we believe this is a good solution. We're out talking to the Pacific Island community and the various groups and sponsors involved with this, and so far their response has been positive."
He added: "I think we'll put on another great event for Auckland."
MPI contacted Ateed on Monday, he said, with concerns about how the festival would impact on biosecurity efforts within the 1.5km radius containment zone. The amount of food on site at the festival, and how it would be managed, was a major concern given the restrictions on the movement of fresh fruit and some vegetables within the exclusion zone.
"At Pasifika we're talking about an event where 40,000 people will be coming in and out of the Western Springs Park area each day and obviously a huge amount of fruit and vegetables being brought in and out of that area," Mr O'Riley said.
"So the issues around people not being able to take food away, food having to be destroyed each night so that it wasn't there and could be infested, those were the issues."
Organisers looked at "a range of venues", but after a feasibility study on two short-listed sites, settled on Hayman Park.
"It's an excellent venue, good public transport and good capability to be able to host the event," Mr O'Riley said.
MPI would "bear the cost implications" of the move, he said, but that had yet to be calculated.
The total number of adult Queensland fruit flies found in Auckland stands at five - four males and one female. One pupa and 39 larvae have also been found.
* Pasifika Festival will take place on March 14-15, bringing the "sights, sounds, tastes and colours of the Pacific" to Auckland, with 11 Pacific Island villages and more than 1000 performers showcasing the best of Pacific Island music, dance and culture.