The building will be brought up to 67 per cent of the National Building Standard after Wellington City Council forked out an extra $16m for strengthening and upgrades.
The temporary site includes a large window members of the public can look through to watch dancers rehearse.
"People love the fact the ballet is in Wellington but they don't often get to see them training, and when they perform it's a good opportunity to see them, but it's not always accessible for everybody", Mayor Justin Lester said.
The Royal New Zealand Ballet is currently performing Black Swan, White Swan. Photo / Supplied.
RNZB Executive Director Lester McGrath said they were looking forward to using the space starting with Bold Moves in July and then a production of Hansel and Gretel this Christmas.
"We are also looking forward to our ultimate return to the St James, with seismic strengthening complete and improved facilities for audiences and artists."
The building is prefabricated and once the ballet moves back to the theatre is could be repurposed at the site, house other arts and culture activity, be moved elsewhere, or sold.