Constructed by the Gunditjmara people more than 6,600 years ago, it is older than Egypt's pyramids.
While the aquatic system was known to archaeologists -- it was added to UNESCO's World Heritage List last July -- additional sections were revealed by the fires that have ripped through the state in December.
Gunditjmara representative Denis Rose, project manager at non-profit group Gunditj Mirring Traditional Owners Aboriginal Corporation, told CNN that the system was significantly bigger than what was previously recorded.
"When we returned to the area, we found a channel hidden in the grass and other vegetation.
It was about 25 meters (82 feet) in length, which was a fairly substantial size," Rose said.
"It was a surprise continually finding new ones that the fires revealed," he added.
UNESCO said Gunditjmara people used the system to redirect and modify waterways to maximize aquaculture yield. »