The Clyde Mountain fire has damaged the Eurobodalla Regional Botanic Garden grounds at northern Mogo, but the recently constructed and renovated centre survived.
The new building included a visitor centre, herbarium, café and education hub.
The Eurobodalla Shire Council said it was constructed to high fire standards, using selected hardwoods, "with these conditions in mind".
The building was handed over to ERBG Manager Michael Anlezark on Friday, December 20, and has yet to be officially opened.
"There has been extensive fire to the grounds," the spokesperson said.
"Other damage will be assessed as soon as it is safe to do so and resources permit.
"For safety reasons, the site will remain closed to the public and volunteers until further notice."