A tow truck has arrived at the scene to take away at least one motorcycle.
A detour is still in place through Saleyards Rd and there are no details of when the highway will be reopened.
UPDATE 8.30am
A man has died after his motorcycle came off the road north of Whangarei this morning.
The rider was found dead by a member of the public on State Highway 1 at Kauri around 4am. His motorbike was discovered nearby in a ditch, police said.
SH1 north of Apotu Rd was closed and diversions were in place via Saleyards Rd.
The serious crash unit is at the scene.
7.30am
A fatal crash near Kauri, north of Whangarei, has closed SH1.
Police and emergency services have shut down the road following the crash at 4.15am today.
Diversions around the scene are through Saleyard Rd and Vinegar Hill Rd.