Local Government NZ says 25 per cent of the mayors elected in the 63 local councils that have declared results so far are women, up from just 19 per cent last time.
And although our biggest city, Auckland, has re-elected 66-year-old Phil Goff, five of the 63 mayors named so far qualify as "young" - under age 40.
One of them, new Hutt mayor Campbell Barry, is believed to be the youngest mayor ever elected in New Zealand, at just 28.
"The election has been a modernising one - throughout the country, the results appear to have produced a re-balancing of the councils and the mayoralties, with voters choosing to elect more women and youth than ever before," he said.
"It does seem to be the zeitgeist - people are wanting to see greater change in our local representatives."
Two-fifths of the 63 councils elected so far have elected new mayors - seven women and 18 men.
The biggest upset seems likely to be in Wellington, where Sir Peter Jackson-backed councillor Andy Foster is 715 votes ahead of Labour incumbent Justin Lester, with 10 per cent of the votes yet to be counted.
In Hutt City, Labour-aligned Barry ousted conservative sitting mayor Ray Wallace.
In Dunedin, Aaron Hawkins became what Edwards said may be the first official Green Party candidate to win the mayoralty of a major city, although other Green supporters have won other mayoral contests under other banners.
Hamilton's new mayor, Paula Southgate, who unsuccessfully moved a motion to declare a climate emergency in the city recently, beat incumbent Andrew King.
In Tauranga, businessman Tenby Powell convincingly defeated incumbent Greg Brownless.
But 38 of the country's 63 districts that have declared so far re-elected sitting mayors, including Liane Dalziel in Christchurch and Sir Tim Shadbolt who won a record ninth term in Invercargill.
Edwards said it was hard to see any clear ideological trend in the results, but "if anything, it seems to me that it moved more to the left-wing".
"Certainly there is a more liberal direction, and by that I mean those candidates that stood on more progressive and environmental platforms seem to have done better than in the past," he said.
Local Government NZ said the overall voter turnout was 44 per cent, up slightly from 42 per cent in 2016 and 41.3 per cent in 2013.
But the vote collapsed in Auckland, by far the country's biggest council - down from 35 per cent in 2016 to just 30.4 per cent, the lowest in the country.
The turnout was also low in other big cities such as Hamilton (32.3 per cent), Wellington (35.8 per cent) and Christchurch (38.8 per cent).
The highest turnouts were in small rural councils led by Grey District (63.1 per cent) and Westland (60.7 per cent).