The Dunedin City Council was to spend $41,000 on the work, which would see a small team of specialists replace some of the monument's ornamental finials and carry out seismic strengthening work, council parks and reserves team leader Martin Thompson said.
Other finials would also be repaired, as would water damage to the structure's terrace and lower chambers, and corroded steel crimps would be removed, he said.
The work was expected to begin later this month and take up to six months to complete, depending on the weather, and would include about three months of on-site work, he said.
The safety work would probably be followed by a more extensive restoration within the next three years, although that was yet to be priced and would need approval as part of next year's annual plan process, Mr Thompson said.
The monument had received some initial repairs last year, after a complaint about its shabby condition, but more work was needed, he said.
The structure was still considered safe in the short term, but the "pretty urgent" work was needed to ensure it remained so, he said.
"There's corrosion in some of the metal rods that connect some of the stonework. That's the work we are doing . . . to make it safe."
The work was the latest spruce-up for the monument, which was built in 1864 to honour Captain William Cargill and placed initially in the Octagon.
It was moved to Custom House Square - now the Exchange - in 1872, a history on the council website said.
The council had worked with the New Zealand Historic Places
