The work, likely to cost less than the budgeted $1.3 million, started above State Highway 6 in March and involved drilling and blasting two areas, known as Zeus Column and Cling On, both on the Queenstown side of the bluff.
Opus civil engineer and project engineer Reece Gibson said about eight Geovert staff were working at a height of about 170m, attached by harnesses and working from two drill rigs ''on wheels''.
With blasting, hand-scaling, sluicing and monsoon rock removal work complete, staff were drilling into the Zeus Column before inserting large bolts - flown to the site by helicopter - which would then be grouted in place to prevent further major rock falls on to the highway below.
''They know that from time to time we will require money to deal with urgent issues here.
''I've got to put up a good case for it, often at short notice.
''We applied for funding for this in November [and] I was able to expedite the approval process, so we actually had tenders out early in January.
''It was important enough [that] actions had to be taken immediately.''
Mr Gibson said because the site was not visible from the highway, motorists were unaware of the scale of work taking place on the bluff, or the risks they faced if it was not done.
''The alternative is something comes down and the road's closed for several weeks.
''Or, somebody's killed [by a rock fall].''
Intermittent closures of the highway on either side of the bluff were still in place, but no further hour-long closures were planned.
The anticipated completion date is May 30.
