NZTA said the work to remove the trees at the northern end of The Kilmog hill, about 20km north of Dunedin, would begin on Wednesday and would take up to three days.
"We need to safely remove a number of hazardous trees on a slope bordering the highway.
"Recent site inspections by our highway maintenance team showed that several trees have lost big bows or already collapsed on the slope while others are on a significant lean with minimal ground support.
"We need to get these trees safely felled before winter," senior network manager Chris Harris said.
The work would take place between 7am and 4pm each day and road users should build in five-minute delay across these days.
Mr Harris thanked all users of the highway for their patience around road crews and for following directions of the traffic management team.
If everyone built in a few extra minutes, that would reduce pressure on their journey time, he said.
This work was weather dependent, so if it continues to rain this week, it may be pushed out to later in the week for a start time.