The remedial work is part of the council's response to the latest attack from heavy seas, which has seen the dunes cut back to just metres away from the Kettle Park sports ground light poles.
Trucks were yesterday dumping sand by the eroded area, with two diggers depositing it over the edge of the dune face.
The recent problems became clear late last week, when it was discovered the sand dunes had receded close to the lights.
The council has a stock of sand, dredged from Otago Harbour and stored at Tahuna Park, but had to wait until campervans parked in the area for the Rugby World Cup left on Monday before the sand could be accessed.
At the site of the erosion yesterday, council sports fields and facilities officer Harold Driver said the electricity to the lights, which was switched off last Friday because of safety concerns, would remain off for the time being.
The lights were not required in summer, so that aspect of the problem did not require an immediate solution.
The remedial work, expected to cost about $60,000, would take two days and be finished today.
Mr Driver said the work was just a "stopgap" measure, and staff would check the site daily to make sure the sea did not make further inroads.
Parks and reserves team leader Lisa Wheeler said late last week the heavy seas that had hit the area recently were expected to subside.
Otago Daily Times readers have responded to recent stories about the issue, notifying both the newspaper and the council Tomahawk Beach had also lost much sand.
At Tomahawk yesterday, it was clear the toe of the dunes had been lost to the heavy seas, with a pathway that led down to the beach ending in a steep drop.
Ms Wheeler said beach had been checked, but it had been decided no action was required.
