The original mausoleum was built in the cemetery about 20 years ago.
The extension followed five years of negotiations between the Cobram Cemetery Trust and the Victorian Government's Department of Health and Human Services.
Trust president Dianne Lindhe said the project was a wonderful achievement.
“We had such a long battle and the extension on the mausoleum is great for the town and community because we were getting low on space,” she said.
Trust member Rachel McKay said the mausoleum was built during the coronavirus pandemic.
“It was built by about August-September last year,” she said.
The mausoleum was blessed by Cobram priest John Corcoran, followed by a ribbon-cutting ceremony.
Moira Shire Mayor Libro Mustica spoke at the event, which was attended by Cemeteries and Crematorium Association of Victoria president Judith Voce and member John McCormack.
The original mausoleum was a vision of Italian community members who approached the Cobram Cemetery Trust.
The Cobram mausoleum was fully built with the funds from sale of crypts and the expansion was funded through the Cemetery Trust reserves.
The opening on March 21 was followed by a gathering at Barooga Sporties.