The main arterial route remains under stop/go management between Barrytown and Punakaiki and delays of up to 30 minutes are still likely.
The road closed completely at about 3.30 am this morning.
Hokitika Airport recorded just over 80mm of rain from 12 to 8am this morning, with 26mm falling between 2am and 3am.
Greymouth saw just over 60mm in the 12 hours to 8am.
SH6 through the Buller Gorge is also under stop-go management due to flooding and a lower temporary speed limit is in place.
Grey District Council warned that access to Moana Rd via Stillwater is closed due to flooding, with Kaiata to Stillwater now open after an earlier closure.
Crews were also monitoring Arnold Valley Rd, Inchbonnie, Paroa and other "known trouble spots".
Grey District Council said a number of local roads had suffered damage in the region and repair work was likely to continue for the rest of the week.
People are being asked to take extra care on the roads and avoid driving through floodwaters whenever possible.
Planned work on Milton Rd up Arnott Heights has also been postponed until tomorrow as crews deal with the aftermath of the heavy downpour overnight.
- RNZ and APL
