Two large slips came down on to the highway during last week's heavy rain and flooding.
NZTA Waka Kotahi journey manager Nicole Felts said more material than expected had to be removed from road, including large boulders that first had be broken up.
Contractors have extended their workdays to start at 7am and finish at 6pm to get through the cleanup sooner.
Thirty minute delays are expected at the rockfall site at the Forsyth Barr Stadium end of SH88, near the intersection with Parry St.
Traffic control is in place at the site, keeping the road to a single lane.
Investigations are continuing at the Burkes slip site to "understand the extent of the damage", Felts said.
Traffic management is also in place in Burkes, but delays are likely to be minor.
