Stabilisation work is continuing at two slip sites on State Highway 6 between Haast and Hawea.
Access is still restricted to one lane at the site where a large rockfall came down on the highway about 15km south of Makarora three weeks ago.
New Zealand Transport Agency senior network manager John Jarvis said the slip - which initially closed the road for three days - was now stable and ''quite safe''.
However, considerable ''tidying up'' was still required at the site.
A large bund had been created at the bottom of the slip to prevent any debris falling on the road.
NZTA wanted to move the highway out from the rock face but needed to wait for the loose material to settle and compact.
''At the moment it's likely to remain single-lane for a few more weeks,'' Mr Jarvis said.
It would be close to two months before the road was sealed and fully operational again.
Work at the Diana Falls slip on SH6 in the Haast Pass is also progressing.
A NZTA spokesman said good weather had enabled drilling of the anchor posts for the first of the rockfall fences to be completed and for work to begin on the anchor posts for the second fence. Installation of the mesh for the first fence should begin next week.
