The building, which first opened in 1861, is the oldest operating synagogue in mainland Australia.

Work, which has been funded through a combination of Heritage Victoria, the Jewish community and philanthropic trusts, is being carried out on the external structure and is expected to be completed by December.

Work will begin on the internal structure in February, which is expected to continue until May.

Ballarat Synagogue president John Abraham said it was the first upgrade other than the odd coat of paint the building had seen since it celebrated its centenary in 1961.

"It was built at the time that Ballarat was just turning from a tent city into a substantial town," Mr Abraham said.

"There was a bit of work done on it in 1961, but it hasn't had more than a lick of paint here and there since."

Mr Abraham said the building was heritage-listed as was a tree out the front, with heritage architects having gone through the building closely in order to create the restoration.

"This is a process which is now happening, after three years of preparation," Mr Abraham said.

"While COVID has meant a slight delay and a lot of normal face-to-face meetings have been held remotely, we're probably only six months behind where we hoped to be."

Mr Abraham said the congregation was now small compared to what it once was, with many members coming to Ballarat from outside the region.

"Back in the 1870s, 1880s, there were thousands of Jewish people living in Ballarat, but as the years went by, a lot have moved away to study and have settled elsewhere," he said.

"Me, myself, I'm one of eight and I was the only one to study in Ballarat.

"The congregation is much smaller than it once was."

To learn more about the history of the Ballarat Synagogue, click here.