SH25 towards the Coromandel and in Tairua will also be at its busiest this afternoon and Friday and Saturday morning.
Those in Canterbury will also be met with a slow journey towards popular holiday spots with SH79 in Geraldine heading west heaviest between 11am and 6.30pm today and Friday, Saturday and Sunday mornings. Southbound on SH1 between Ashburton and Christchurch is heavy between 2pm and 6.15pm today, 9am to 11.15am on Friday, 10am to 1.45am on Friday and 10.15am to 11.45am on Sunday.
The agency has advised northbound traffic from Wellington to be heaviest between 11.30am and 6pm today, and from 9.30am to 2pm on Friday.
As Wellingtonians return home after Easter, southbound traffic is predicted to be heaviest between 1 and 5pm on Sunday, and from 12 - 6pm Monday.
Waka Kotahi NZTA Regional transport system manager Mark Owen said all routes out of the capital were likely to be more congested than usual.
"We know the traffic will be very heavy on SH1 up the Kāpiti Coast but also people heading over the Wairarapa Region and beyond on SH2 – those roads will probably be busier than normal."
Wet weather likely today and Friday could also make driving more challenging.
"Our plea is that everyone drives to the conditions," Owen said.
"It's really important if it gets wet, we advise people to slow down, be mindful of the stopping distance, and keep an eye out for any hazards – if there's heavy rain there may be flooding or debris.
"Be patient, plan ahead and have a contingency plan if something happens and traffic is blocked."
Owen advised motorists to check their travel time with the transport agency's predictive tool, which had been accurate in forecasting busy periods over previous long weekends.
"We encourage people to go on and look at when the busiest times are going to be, and if they can avoid those times that will make their journey a bit easier and a bit smoother."
"It just gives people some indication that if you are travelling through those busy periods, you will need to allow extra time because it is inevitable there will some delays."