High-pressure hoses have been used to wash the rubble off of the rock shelter in Otira Gorge.
A large rockfall occurred mid-afternoon on October 18 on the West Coast side of Arthur's Pass.
Work to clean the rubble began on Monday, a spokesperson for Waka Kotahi NZ Transport Agency said.
It will continue for five hours each day and is expected to take five days to complete.
The section of State Highway 73 remains closed while the work is undertaken.
During the rockfall, a truck driver was forced to seek refuge under a purpose-built concrete rock shelter.
The truck and trailer was travelling down a steep section of the alpine route when it was forced to come to a stop under the rock shelter, as boulders one metre in size tumbled down, crashing on to the road and blocking traffic.
The driver was able to get out of the truck and was picked up by road crews and taken to Arthur's Pass.
The section of SH73 remains closed while the work is undertaken.
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