"Please pass with care and expect delays, as traffic is building in the area", the traffic agency tweeted.
The Easter exodus out of - and back into - main cities means slow journeys at times this holiday weekend.
Waka Kotahi NZTA this week released traffic predictions based on the patterns and busiest periods of previous years.
Heavy traffic periods still to come include between 9am and 12.30pm tomorrow and 9.15am and 2pm on Monday for those travelling south on SH1 between Manukau and Bombay.
Traffic would also be at its worst on SH2 between Paeroa and Waihi between 11.45am and 1.15pm tomorrow.
Those in Canterbury could expect slow journeys towards popular holiday spots, with SH79 in Geraldine heading west heaviest tomorrow mornings.
Southbound on SH1 between Ashburton and Christchurch would be busiest between 10.15am and 11.45am tomorrow.
The agency has advised southbound traffic to Wellington to peak between 1pm and 5pm tomorrow, and from noon to 6pm on Monday.