SH2 north and south of Te Karaka is also closed due to flooding. The small town is 30km northwest of Gisborne.
Police say there are some people stranded on the highway between two flooding flashpoints, but they are not in any danger. It is not known how many vehicles have been trapped by floodwaters.
Senior Sergeant Ross Smith said police were making their way to the vehicles and would check on the motorists and evacuate them if necessary.
"At this stage it has stopped raining in the area and it looks like there may be a break in the weather. But we need to check on these people to make sure they are alright and see if the highway is now passable," Mr Smith said.
The highway will be closed overnight due to the weather conditions and will be reassessed in the morning.
Floodwaters have also risen sharply in Gisborne city, with the northern route linking the city to the East Coast now closed.
There is also significant surface flooding throughout the city and surrounding rural areas.
Wairoa Civil Defence Emergency Management says that there was river debris on Kopu Road and surface flooding on many roads and in Wairoa township.
Wairoa CDEM staff continue to monitor the situation and ask that people take care on roads and watch for roadside slips.
Over 24 hours the rainfall was around 180mm in places, while in some places half of that.
The forecast for the sea swell along HB coast is not causing concern. Although it is a sizable swell it is not unusual for this coastline. The swell should peak around noon today which coincides with a high tide but does not have enough energy to breach barrier beaches.
The swell forecast for Wednesday is for a longer swell (compared to the peaky one of today) which should only reach heights of around 60% of today's seas.
For more information on getting ready to get thru a civil defence emergency visit www.hbemergency.govt.nz or visit Hawke's Bay Emergency on Facebook or Twitter.
