''Depending on what the weather does, caution needs to be exercised everywhere,'' New Zealand Transport Agency (NZTA) Central Otago area manager John Jarvis said.
''It's going to go on for several weeks because of the state of the ground conditions right through the network.''
Yesterday, several state highways in the South remained closed.
State Highway 94 from Te Anau to Milford Sound was closed because of snow between the Hollyford turn-off and Murrell Creek Bridge, while SH1 between Waipahi and Arthurton remained closed because of a washout.
Although SH6 between Cromwell and Queenstown was reopened on Sunday night after a major rockfall in the Kawarau Gorge at Crawfords Hill, 2km west of Roaring Meg, drivers still needed to take care, Mr Jarvis said.
''I think it's pretty much cleaned up there, but we are urging caution.
''We've still got some concerns, particularly around the gold mining centre ... We're still having a few rocks come down from time to time.''
NZTA Otago-Southland operations manager Roger Bailey said the section of state highway, closed since Thursday was likely to remain shut for several more days. Fixing the washout was a ''tricky job'' which would take two or three days to complete, he said.
Detours are in place along West Otago Rd and Waipahi and Young Rd at Arthurton.
Traffic on SH8 between Alexandra and Cromwell was reduced to one lane yesterday as contractors worked to clear a landslip that happened at the weekend. Several other Central Otago roads, mostly gravel roads in the Maniototo, remain closed because of flooding and wash-outs.
Council infrastructure services manager Jon Kingsford told yesterday's Cromwell Community Board meeting nothing could be done until the ground dried out.
He described the weather in recent weeks as a ''perfect storm''.
''We had unprecedented rainfall, followed by unprecedented snow, followed by unprecedented snowmelt,'' he said.
