Hamilton police are calling for calm on the roads as Boxing Day shoppers cause chaos.

There've been four crashes on Wairere Drive as crowds head to The Base.

MORE: Consumer chaos at Boxing Day Sales 

Traffic is backed up along Wairere Drive, and Te Rapa Road in the north and south is blocked up.

Senior Sergeant Andrew Townsend said there are huge delays.

"The key message from Police today is to not be distracted. Be patient."

"If you are travelling to the Boxing Day sales, you will get there."

North of Auckland there's heavy traffic going north from Silverdale and congestion in Warkworth and Wellsford.

A serious crash has closed the Waikato Expressway State Highway One link to State Highway Two south of Bombay for eastbound traffic.

A crash is blocking a lane southbound on State Highway Five west of Ngongotaha near the intersection with Western Road.

In the Wellington area there are delays for northbound traffic on State Highway One at Otaihanga roundabout due to holiday traffic.

A truck has rolled on State Highway Six between Nelson and Havelock near Whangamoa and is blocking one lane.