"We thought we were only going to get about 25,000 items into this space, but the team have worked so hard and diligently that they've actually got just on 40,000 items," he said.
"We are really pleased to be able to have all the elements of a library covered. As well as having thousands of books to choose from, we have a research and heritage section any library would be proud of."
Applause was heard when he assured the crowd it was a "temporary" home.
The new library space opens into a large room housing computers, a study area, research books, and a service desk. An octagonal vestibule leads off into a non-fiction area, and the larger fiction room - complete with a children's section - and seating area.
When moving, council manager of visitor experiences Sally Jackson said they had considered what was loved about the former library - such as study areas - and tried to recreate it in a way that suited the new 550sq m space.
The transition also included respecting the heritage of the building, finding ways to bring in light - such as opening boarded-up windows - and reconfiguring the planned shelving to better suit the space and fit an extra 15,000 items.
The biggest challenge faced was the public perception of the temporary facility, and making sure it lived up to expectations, Ms Jackson said, but from yesterday's reaction she thought it was well received.
Friends of Napier Library spokeswoman Susan Wylie said they were very supportive of council's effort to keep library services at a high level.
"We realise it's a smaller space, it's a temporary space, but it's very welcoming and will get lots of use. "
MTG director Laura Vodanovich said there had been little disruption to the MTG during the move, and it was reaping the benefits of other changes to make it and the library align better -especially the removal of the MTG entry fee.
"The front-of-house staff have completely changed their definition of a quiet day now - it's about 500 people, whereas before 500 people would have been a huge day, so it's fantastic.
"I'm loving seeing this space open up again for public use rather than closed for storage."
The transition has also included improving the accessibility of the site - a ramp has been built outside the foyer, parking improved, and bus routes altered.
If a book is not available at the MTG site, it could be retrieved from either the Taradale library or from the retrievable storage location in the CBD. Reservation fees have been removed.