Young people often felt frustrated as they believed their voices weren't heard, Ms Kearns said.
"There may even be a case to consider whether 18 is the appropriate starting age for democratic participation. But certainly on this issue there is a strong case to enable younger New Zealanders to participate."
Youthtown asked 25 of its youth squad members if they wanted to vote. All 25 did: 19 wanted the current flag to stay, four preferred the new flag and two said they wanted an alternative option.
Some squad members saw the flag referendum as a waste of money, while others believed a new flag would be a nice change for the country.