Diversions are in place along Mountain Rd and SH12.
The truck driver suffered moderate injuries in the crash.
A Fire Service spokesman said a truck rolled near the Northland town of Kaiwaka about 4am.
The New Zealand Transport Agency warned motorists to expect delays.
"Emergency services are on site. Please delay your journey or use an alternative route," NZTA said on its website.
Northbound drivers can take Kaiwaka-Mangawhai Rd, onto Moir St, left onto Molesworth Dr, left onto Mangawhai Heads Rd, right onto Cove Rd, before continuing through Waipu and back to State Highway 1.