A car towing a boat has hit a power pole, causing lines to come down across State Highway 1 just north of Kaiwaka, which has ignited a scrub fire.
Police say the road south of Baldrock Rd has been blocked.
Emergency services were called to the scene shortly after 3pm.
A Fire and Emergency New Zealand (Fenz) spokesman said the crash had caused a scrub fire reaching about 100m by 20m.
Four fire crews with 16 firefighters and one tanker are at the scene working to put out the blaze, he said.