This would mean using the exhibition hall with its 9m internal stud and the plenary theatre a level above.
The hotel's elliptical-shaped core has risen beside TVNZ's headquarters while the exhibition hall is at the Albion Hotel end of the site.
The hotel would have an underground gym and porte-cochere or entranceway accessed off Nelson St, Mallet said.
Fletcher Construction started work on the site 22 months ago and according to Mallet it is due to be finished in the latter half of 2019.
"There are just over 400 people working on the site but since work started, more than 900 people have been employed on-site."
The 8100sq m exhibition hall will be a flexible area able to accommodate events for up to 4000 people and conferences catering for 3150 people.
But splitting the hall will be possible and direct truck access will be available off Hobson St.
The plenary theatre above the exhibition hall on level five will seat 2850 people.
NZICC conferences announced:
• Tripartite colorectal meeting, February 2020, 1200 delegates
• International Association for Prevention of Blindness, March 2020, 2000 delegates
• Asia Pacific Academy of Ophthalmology, March 2020, 3500 delegates
• World Veterinary Congress, April 2020, 1200 delegates
• World Organization of Family Doctors Asia Pacific Region, July 2020, 2000 delegates
• World Congress of the International Union of Food Science and Technology, August 2020, 2000 delegates.