Aucklanders who drive to work are spending an extra 172 hours, or four working weeks, stuck in traffic every year, new data from GPS technology company TomTom shows.
That was well up from 2014, when Aucklanders were spending an extra 95 hours a year stuck in traffic.
The company's latest traffic index shows congestion in Auckland added 45 minutes to a trip that would usually take an hour in free-flowing conditions.
The data showed Auckland was New Zealand's most congested city and was ranked 47th globally. Its traffic was worse than Hong Kong, which has a population of 7.2 million.
Editor of the Auckland-based Transport Blog Matt Lowrie said TomTom's figures did not take into account people who drove at off-peak times.
"What it doesn't count are all the people who aren't sitting in the traffic, who might be on a train or on a bus, who aren't contributing to that congestion, who are moving.
"There are a lot of people who just don't count in the report, so it's not necessarily a complete picture of congestion - it's a picture of road congestion, but not necessarily total congestion."
More than half of Aucklanders were opting not to drive their car into the city during the morning rush, Mr Lowrie said.
Instead, they were taking public transport, walking or cycling.
Elsewhere, traffic also worsened in the capital, where Wellingtonians added an extra 43 minutes to their drive times.
Congestion in Christchurch has increased the least, but drivers still faced an extra 29 minutes' travel time each day.