Nelson's council has had to provide a loan so repairs to the historic Nelson Centre for Musical Arts can be finished.
The 117-year-old building has been closed since 2013 because of its earthquake risk.
The Nelson Centre for Musical Arts Trust recently told the council it was short of $900,000 to complete the upgrades, after more seismic strengthening work was needed and asbestos was found in the building.
Nelson City Council said it had already made a significant, $3 million ratepayer contribution to the project and it was not in a position to give more.
But it offered the trust an interest-free bridging loan of up to $680,000 while ithe trust carried out further fundraising.