Motorists are being thanked for their patience but advised to plan their route and time of travel while a major artery into Whangarei's city centre is blocked.
Whangarei District Council is warning that the closure of Nixon St on either side of Mill Rd, between Kamo Rd and Mair St, will take some getting used to.
"We too will just be getting to know how the traffic responds to the changes, and we will be altering the lights to best suit the traffic, but it will take a few days to get this right," WDC spokeswoman Ann Midson said.
"The best advice is head out a bit earlier or later than usual, stay calm, plan ahead, give everyone a fair go, we are all on a learning curve."
The road was closed on Monday and will remain so until May while power, phone, water and sewerage lines are moved.
Road widening work will begin in spring and could be finished by Christmas. Morning peak seems to be between 8.45 and 9.15am, so avoid that drive time if you have the option, and avoid Manse St altogether if possible, Ms Midson said.
"If not possible to avoid it, exit Manse via State Highway 1 or Lupton to avoid queues on the Bank St end and traffic is lighter on Mill Rd than Kamo Rd. Drivers can get from Mill Rd into Hatea Dr through Mair St and from Kamo Rd through Deveron St."
Queues are expected where traffic funnels into the Mill Rd, Kamo Rd and Manse St intersection at peak times.
"This piece of road has been a major problem for years, so fixing it is also a bit of a major," Ms Midson said.
The work is one of the final stages of the council's 20-year Transportation Strategy which included the Porowini Ave extension, Kamo bypass and Lower Hatea River Crossing.
WDC Senior Asset Engineer, Greg Monteith, said a dramatic increase in traffic at the Nixon St intersections had caused queuing and accidents, and the volume was expected to grow.
Meanwhile, major work continues with the four-laning of State Highway 1 through Whangarei. New Zealand Transport Agency is now upgrading Western Hills Dr from Wilson to Fourth Aves.
That work and the Nixon St project are considered far enough apart not to affect further traffic flow problems.