No cost estimate was available for signage, which could be in Maori as well as English.
Committee chairwoman Ann Hartley supported the approach.
"We will go slowly and sensibly and not build it into a big-budget item."
Forum chairwoman Sandra Coney said councillors wanted "something simple" in the way of staged steps "without making too much of a meal of it".
The policy would start with parks - many of which were already relying on smokers' voluntarily refraining - and spreading to town centres and streets across the region.
All regional parks and city parks in Waitakere and Manukau already had smoke-free signs.
Deputy Mayor Penny Hulse said it was a good way of making people think twice before lighting up.
However, councillor Dick Quax voted against it.
No survey was available to show whether the approach had caused people to stop smoking in Manukau.
He said "no amount of big-city nannying" would get addicted smokers to give up and he thought council effort would be better spent on stopping smokers littering footpaths with their cigarette butts.
Cancer Society chief executive John Loof supported the non-regulatory approach towards a consistent and region-wide smoke-free policy for parks, playgrounds and sportsfields.
He said the Auckland Plan wanted these public areas smoke-free by 2025 and reducing smoking to less than 3 per cent of the population in the next 13 years.
"The average age that children start smoking is 14 years and research has shown that the more places that children see smoking the more likely they are to start," he said.
Other cities, such as Tokyo in Japan, use smoke-free signs but also enforce the ban with fines.
CIGARETTE-FREE
Proposed
* All public open spaces, including skate parks, civic squares and pedestrian malls.
* Council-run stadiums, outdoor swimming pools and outside community centres and halls.
* Public transport hubs, public events using ratepayers' money.
Already smoke-free
* All regional parks.
* Mt Smart Stadium. Auckland Zoo, Eden Park.
* Mangere, Otara and Botany Town centres.
* AUT University.
* University of Auckland.
* Parks in the former Waitakere and Manukau City and playgrounds and sportsfields in Waitemata and Puketapapa Local Board areas.
WILL SMOKERS HEED SIGNS?
Smokers on Queen St yesterday had mixed reactions to the council's smoke-free city proposal.
Business student Selita Bulitavu, 20, has been smoking for two years and said if the proposal was passed she would respect signs prohibiting the practice in public areas.
"I would respect that sign and I wouldn't smoke in that public area.
"I don't want to be a bad influence around little kids."
Peter Josephs, 31, has been trying to cut down the amount he smokes and said the council should just ban it.
"They need to ban smoking in general if they're going to do these things. They're wasting money on signs."
The father of two said he would not care if signs were put up prohibiting smoking in public places. "I'd probably stand right next to it and lean on the sign and have a smoke."
Stacey Leef, 16, said: "If there were other people smoking around the signpost, then I would too."
Her friend Lianna Duran, 17, said: "If there were people around checking to see if we were smoking, then I would stop."
