Falling rocks have seriously damaged the popular Crown Tramway Track at Karangahake.
The Department of Conservation (DOC) has temporarily closed the track while DOC staff and contractors will be working to bring down any rock which is threatening to fall.
They will then stabilise the bank above the affected area and the barrier and track will be repaired before the track can be opened.
Access to the upper Crown Track, Underground Pumphouse and Dickey Flat is via the Windows Walk.
A short section of track surface and a safety barrier need repairing before the section can be reopened.
The bank also needs to be stabilised and it is expected to take a few weeks to carry out.
DOC visitor assets programme manager Jeff Milham said the repair job is getting underway.
"The initial rock fall occurred between Christmas and New Year but there has since been further rock fall from the bank above the track,'' he said.
''This is seemingly a natural event, we know these happen from time to time in the gorge.''
Mr Milham said the affected area is in a precarious part of the gorge where the track is narrow with a steep drop off.''
The popular Windows Walk and other attractions are still accessible to visitors.