The production's cost was at the higher end, its local cast had been rehearsing since October, and its technical aspects were beyond what the Society had dealt with before.
While the show is an international hit, its cast is made of local Napier Operatic Society members, from James Wright as Bert, Kelly Davis and Johnny Duncan playing Mr and Mrs Banks, and Laura Jeffares as Mary Poppins.
Four months of planning, special crews, and a "lot of money" had been spent so beloved scenes could be recreated - Mary Poppins can fly, Bert dances over the ceiling, and people disappear inside chimneys.
"We do as much on stage as happens in the movie," Mr Collier said. "I think people are surprised they're seeing that sort of magic live on stage."
"I think this is one of the most spectacular shows we've had in Napier, and I've done some pretty big shows."
Napier Operatic Society treasurer and past president Lesley Carthew said they had been "blown away" by how audiences were reacting to the production.
"I can't believe the response that we have had," the Musical Theatre New Zealand president said. "Everyone is coming out of the theatre just buzzing."
As well as the production of the show, Mr Collier said the well-known story of Mary Poppins was also drawing crowds - "people saw it as kids, and now they're bringing their kids to see it."
Napier Municipal Theatre client relations manager Ian Reid said there had been strong bookings, with nightly shows nearly full, and Sunday's matinee performance "completely sold out".
"They're getting standing ovations every night," he said. "I sat in on the first night and I was just blown away by the talent."
When asked what he thought was pleasing audiences so much, Mr Reid credited the local-cast.
"It's such a quality cast, and you can tell they're doing it for their love of theatre," he said. "Hawke's Bay's got a lot of talent."
The show is directed by Wendy Revell, with musical direction from Marc Oldershaw, and choreography by Leanne Murphy.
-Tickets are still available for the last week of Mary Poppins at the Napier Municipal Theatre, from Ticketek.