"There’s no point in waiting until we get all the money that we need, because by that time, there may not be anything left to save," Cargill’s Castle Trust chairman Steven De Graaf said.
"It’s getting to the point where the work is needed urgently, so with the money we’ve got, we’re going to do as much as we can."
He said that involved stabilising the front of the historic building and the main tower before the end of this year.
Over the past year, decay of the building had accelerated.
"A few of the cracks that were in it have got much bigger. There’s a wee piece come down on the back corner in the last six months, and there’s an old rocky support beam that helps support a wall and it’s getting really quite bad too."
Mr De Graaf said the stabilisation work involved putting steel plates around the tops of the walls, and it was hoped that work would be completed by early 2025.
"It has become critical that we get this first stage completed as soon as possible before any walls start to come down.
It was hoped this Sunday’s Heritage Homes Open Day fundraiser would help fund the project.
Between 11am and 4pm, members of the public will go on an 11-stop tour of interesting Dunedin buildings, including a church, a commercial building, an old post office and a "crazy" railway garden.
Another highlight would be an exclusive pre-opening look at the recently refurbished Port Chalmers Maritime Museum, he said.
"This is our major fundraiser for the year and we are hoping to get a good turnout as we are about to make a start on the stabilisation of Cargill’s Castle.
"We hope the public get behind this fundraiser to help save this unique piece of early Dunedin history."
Overall, the project was expected to cost up to $2 million, he said.
