The additions from Austrian manufacturer Doppelmayr are in keeping with the original 25 cars, and boost the number of passengers from 700 per hour to 1100 per hour.
The base terminal foyer was modernised, and extended to ease customer service; and the Wakatipu Room, the main function room in the top terminal, has been extensively refurbished, as part of the complex's first major upgrade in 22 years.
About three administration and eight maintenance staff have been working over the past four weeks.
The remaining 70 staff were on paid leave.
More queuing space has been created in the foyer and a third extra point-of-sale and an express lane have been incorporated.
More space for Magic Memories to trade and to serve gondola customers has been created to the right-hand side of the main entrance.
The terminal building has been extended by about a fifth to the northeast, to accommodate the extra cabins and the associated maintenance.
Skyline Gondola property manager Blair Deasy said the upgrade was mostly mechanical and technical.
"The public are not going to get a faster trip. It's about being more efficient with processing, because there's three tills; and queuing, because there's more space.
"There's a new ball wheel at the top to pull the line, there's a new electric drive motor with back-up diesel engine at the bottom, and a new communication cable between top and bottom terminals."
At the top terminal, the souvenir shop will be modernised with new carpet and lighting and hard surfaces laid by doorways.
The Wakatipu Room has had carpet laid, improved lighting, a sound system and electrical connections installed, and a soundproof divider and theming lines for festive drapes.
The bar size has been doubled and the room can cater for 200 seated or 400 standing.
Mr Deasy said the room was booked for Queenstown Chamber of Commerce and Queenstown Winter Festival events.
