"The fire and water damage that we have found, and the long-lead product we need to source from overseas, makes completion by that date highly unlikely.
"We, like our client SkyCity, are disappointed that the damage the fire caused has made this challenge so difficult but we are working closely together and with insurers to deliver a world-class venue for New Zealand."
Reidy said the fire had affected secondary steel that supports the roof and holds up key elements of equipment.
Areas of the façade adjacent to the roof may need to be replaced, Reidy said, and if this is the case it will require a 12-14 month work programme by the specialist glass manufacturer who is in the United States.
"There has been extensive water damage throughout the building which, combined with the summer heat, has created conditions for mould. That requires the replacement of many of the services and fittings that were installed and has restricted normal access to the site," Reidy added.
"We also need to clean residues from the fire from large parts of the building."
Recovery from the fire at the convention centre will continue for the next few months before major construction work can begin mid-year.