A diesel spill in Northland might have contributed to four separate crashes on the roads this morning.
Police said Ngunguru Road East - north of Whangarei - from Rockingham Rd through to the Ngunguru township was affected.
Inspector Kerry Watson said police have asked the Whangarei District Council to attend and contain the diesel as a matter of urgency.
Motorists should avoid the road or drive at extremely low speed if they had to drive, police said.
A Whangarei District Council spokeswoman said the council was aware of the spill.
Contractors were on their way to the site now.
It was too early to say what might have caused the diesel to be on the road, she said.
