There is heavy traffic between Levin and Wellington, where the All Blacks are playing Ireland tonight.
Waka Kotahi says there are long queues on State Highway 1 between Levin and Ōtaki, and people should plan for an extra hour to 90 minutes of travel time.
There are also reports on social media of packed trains on the southbound Kāpiti line.
The All Blacks are playing the Ireland men's rugby team in the capital this evening.
There are some road closures in the central city just south of Sky Stadium.