The was closed late yesterday morning at Burke Flat, between Haast and Makarora after torrential rain triggered a substantial slip that covered both lanes of the road.
The slip continued to move yesterday and overnight and the clean-up was under way this morning, the NZ Transport Agency said.
In an update around midday the NZTA said the road was open but motorists should expect delays.
Heavy rain overnight also caused rockfalls on SH6 between Kingston and Queenstown, while SH94 between Te Anau and Milford will stay closed today due to a high avalanche hazard.
In a media advisory, the Queenstown Lakes District Council said "caution" was required for motorists travelling around the rockfalls.
QLDC spokesman Jack Barlow said the rockfall was "very minor" and happened on the stretch of highway occasionally when it rained.
"There are no road blockages, or danger [to motorists],'' he said.
Motorists travelling over the Crown Range were advised to carry chains.
While the weather posed some problems for motorists, it brought a dumping of snow to southern skifields.
Coronet Peak Assistant Ski Area Manager Mark Sommerville said they had had 15cm overnight "and the snow is forecast to keep falling for the next two days".
"Everyone up here is raving about the conditions - it’s not often you get a powder day with sunshine and quiet lift queues. We can’t wait to see what the next couple of days delivers.”
