Auckland drivers could be facing "significant delays" after a serious crash involving four vehicles near Warkworth.
Emergency services were called to the scene just after midday, at the intersection of State Highway 1 and Satellite Station Rd, a fire and emergency spokesperson says.
One person has moderate injuries while another has minor injuries, and traffic is blocked in both directions.
The New Zealand Transport Agency posted to Twitter warning of the delays and asking drivers to use SH16 as an alternative route.
"Emergency services are on site directing traffic," NZTA says.
The serious crash unit has been advised.