Central Otago District Council has extended the closure of the reserve to July 9 to allow for work to be completed.
Parks and recreation manager Gordon Bailey said felling had been slower than originally anticipated due to the need to protect the lizard habitat and unique landscape.
Contractors were working with council to look after the landscape, and lizard habitat and trees which impacted on specific lizard habitat were felled with oversight of a herpetologist, he said.
"The team are working as carefully as possible, and Council is supportive of this methodology."
The additional timeframe was not anticipated to impact on budget for the project.
Weather permitting, Mr Bailey said he did not expect any further extensions would be needed to complete work requiring the closure of the reserve.
Next week the trees bordering State Highway 8 will be removed.
Traffic management will be in place at the time and motorists should expect some minor delays during those days.
