Watch NZ Herald Focus: Inside historic St James Theatre

The $65 million restoration of Auckland's St James Theatre is continuing to unearth secrets of the city's past.

An array of artefacts has already been found beneath the historic theatre's floorboards and now a long-forgotten tower has also been discovered.

"Heritage buildings are often complicated to work with," says Steve Bielby from the Auckland Notable Properties Trust.

"There is constant tension between what you can and can't do. Essentially you are designing and constructing as you go depending on how the building steers you - which is not the usual approach to a building project."

"The St James is a private-public project - a partnership between the Auckland Notable Properties Trust and developer Relianz Holdings which is building an apartment building around the theatre. Auckland's rising property prices made the proposed apartment development viable," he says.

"The St James could easily have become today's equivalent of His Majesty's, which was demolished in 1987.

"The reality, though, is that in order for the theatre to survive, it has to sit within a commercial development project like this.

"The standard grant-based charitable trust model of fundraising would not have been able to support a project of this scale with its budget of $60-70 million."

The project has drawn support from Auckland Council, which recently provided funding of $15 million through a suspensory loan, and Bielby is determined that the work on the St James will set a high standard.

Heritage New Zealand has also provided advice and guidance on heritage elements of the building, while also recognising the need for the theatre to function effectively in the entertainment marketplace - as it has done for almost 90 years.

"The St James Theatre project has taught me not to be in so much of a hurry. The building has secrets - and will reveal these only when she wants to."