The cottage is on the Victorian Heritage Inventory and is connected with Ravenswood Run, one of the first tracts of land settled by colonialists in central Victoria.

Aerial images sourced from a City of Greater Bendigo property database show the roof blew off no later than January, 2018.

The building is one of three structures that sit on what is now crown land managed by the Department of Environment, Land, Water and Planning.

The damage to the building came to the department's attention in mid-May.

The Bendigo branch of the National Trust is "very concerned" about the cottage, which sits three kilometres away from the state heritage-listed Ravenswood Run homestead, president Peter Cox said.

"They have not been maintained ... they are a very important part of our history," Mr Cox said.

It can be hard for DELWP to monitor hundreds of historic buildings and other community assets across 22,000 parcels of land in its Loddon Mallee portfolio, DELWP land and build environment programs manager Adam Melis said.

"DELWP manages an extensive area of land throughout the Loddon Mallee Region, extending from Gisborne to Mildura, with a small team to oversee the entire region," Mr Melis said.

"We rely heavily on the community to inform us of matters relating to assets and use of public land, without this support, it is difficult to be aware of the condition of all structures on the thousands of hectares of crown land."

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Mr Cox plans to make contact with DELWP and arrange a meeting to discuss the site.

Member of the public Norm Stimson is concerned about rain further damaging interiors.

He would like to see a tarp put over the roof to stop rain getting in.

He also wants a decision on whether the site will be restored.

DELWP will assess the site within the next three weeks, Mr Melis said. It also plans to look for external funding to repair the roof.

Some buildings and other assets on crown land are managed by committees of management, but that is not the case for the cottage or two nearby, Mr Melis said.

"If there are any community groups or members of the community interested in volunteering to manage these buildings, please contact DELWP at 5430 4444."

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