The document that determines when a lift should be installed in a building to provide vertical transportation is section 9 of NZS 4121:2001 Design for access and mobility: Buildings and associated facilities.
Clause 18.104.22.168 says that, where the above is not applicable a lift is not required, provided the ground floor is accessible and upper floors are accessible for ambulant disabled, for:
Buy NZS 4121:2001 Design for access and mobility: Buildings and associated facilities
From BRANZ Guideline, September 2016
When is a lift (for vertical transport) required?
30 September 2016
Published in building.