"There was not a single group bar one, which is male university-educated high-earners where it's touch and go, that's in favour of a flag change," Dr Milne said.
Support for change increased with household income from 9 per cent of people in homes earning below $40,000 a year to 24 per cent in homes on more than $150,000. But even in that top group, 44 per cent favoured the current flag and 31 per cent said it would depend on the design.
There was a similar gradation with education, with support for change rising from 4 per cent of those with no qualifications to 16 per cent of the university-educated.
Majorities supported the current flag in all regions except Wellington, which also had the highest median income and the highest share of university graduates in the 2013 Census. Even there 42 per cent favoured the current flag, with 17 per cent backing a change in principle and 41 per cent saying it would depend on the design.
Surprisingly, support for change in principle was lowest among young voters aged 18 to 25 (9 per cent) and rose with each age group up to those aged 46-65 (14 per cent), dropping back to 13 per cent over 65.
By ethnicity, none of the 18 Pacific people in the sample supported change in principle, compared with 12 per cent of both Maori and Europeans and 13 per cent of Asians.
And even though the poor and less educated tend to vote for left-wing parties, support for change was much stronger among those who placed themselves on the "right" (17 per cent) than on the "left" (10 per cent).