Traffic is backed up for kilometres near Auckland and Wellington as people return home from their holidays.
New Zealand Transport Agency spokesperson Luigi Cappel said the worst spot was headed north towards Auckland, near Pokeno.
Mr Cappel said there was a six kilometre tail of slow traffic there.
He said traffic on State Highway 1 at Warkworth heading south toward Auckland was free flowing.
Earlier today, the line of traffic had reached about five kilometres long.
Mr Cappel said there was a three kilometre tail of traffic heading from Otaki towards Wellington.
He said he expected the traffic in all the hotspots to build up slightly this evening, but compared to most holiday traffic, it was mild.
Earlier, Mr Cappel said fewer-than-expected people headed home yesterday - which could lead to longer lines today.
"The traffic didn't build up nearly as heavy as we expected ... it wasn't as bad as the same time last year."
The NZTA has encouraged people to check road conditions before they set off and to avoid peak times if possible.
Sixteen people have died on the roads this Christmas break, with the official holiday road toll period due to end at 6am tomorrow. It started at 4pm on Christmas Eve.