"While there were no injuries, and incidents of this nature are rare, we take these extremely seriously."
A source told the Herald that scaffolding material plunged 28 storeys following a incident at the weekend.
The Herald sought further details including the type of material that fell, from what height, how the incident occurred and whether any staff were on site at the time.
Fletcher external relations manager Ellie Martel today said: "We have nothing further to add to yesterday's response."
A WorkSafe spokeswoman confirmed that they will also be conducting an investigation into the incident.
The Commercial Bay $1 billion waterfront site is New Zealand's largest property development and owned by Precinct Properties.
Fletchers was the construction company contracted by Precinct Properties.
A Precinct Properties spokeswoman said they were aware of the incident, having been advised by Fletcher.
"Fletcher have advised us that Worksafe has been notified and Fletcher are conducting an internal investigation."
Construction of the tower, planned to be 39 levels, reached level 31 last month. Tenants in that tower include PwC, Chapman Tripp, MinterEllisonRuddWatts, DLA Piper, Marsh and Spaces.
Precinct also announced last month plans to bring global hotel brand InterContinental to Auckland in a $298 million expansion to the project.