The search for potential unmarked burial sites was done before repairs began on the ACT heritage-listed De Salis Cemetery on the banks of the Murrumbidgee River.

Burrowing wombats and heavy rain have taken a toll on the walls made of local stone which support a raised circular terrace and rare example of a 19th century pastoral station cemetery.

The ACT government's manager of operations of national parks and catchments, Brett McNamara, said the cemetery was raised because the land was too hard to cut grave sites, and to lessen the risk of flooding from the river. There are 16 known graves within the site. Radar indicated an extensive area of previously disturbed ground.

Canberran David Reid, who first visited the cemetery in the 1970s, established a blog to campaign for its restoration.

Mr McNamara said having specialist staff available, including an archaeologist, was part of a significant investment.

''The values we have down there are incredible, particularly with all our minds turning to matters next year as part of Canberra Centenary,'' Mr McNamara said.

Pastoralist and politician Count Leopold Fabius Dietegen Fane De Salis moved his family to Cuppacumbalong in 1855. One of his sons had chosen the site.

One of the few remaining De Salis family members, Adrienne Bradley, said the extent of damage was surprising.

Her great-grandfather George De Salis had built the wall.

Mr McNamara said ACT Parks commissioned an engineer to advise on restoring the stone wall.

''The ACT Heritage Unit and Heritage Advisory Service have provided ongoing feedback. Heritage experts will oversee the restoration to ensure works are in accordance with the site's heritage plan and to minimise impact on existing graves.''