A majority of New Zealanders believe it is time to change the national flag, with more than half favouring a design based around the silver fern, a Herald DigiPoll survey has found.

The poll, conducted during the Herald's series on changing the flag, showed 52 per cent of New Zealanders thought it was time for a new design, with the greatest feeling for change coming from those aged 40 to 70. About 44 per cent did not think the time was right to change.

Asked what they preferred if it did change, 53 per cent of those surveyed said they would like to see a silver fern on the design. The next favourite was the kiwi, with 18 per cent support, 13 per cent for the koru, the southern cross 12.5 per cent, and the tiki with just 1 per cent..

The poll also found that Aucklanders, young adults and the over-70s are more likely to think the New Zealand flag is good enough.

Young adults are also surprisingly the greatest champions of seeing the Union flag retained in a new design.

The mood for change is substantially higher than the last New Zealand poll, by Nielsen for North & South magazine in 2008, which found 25 per cent supported change.

Business leader Lloyd Morrison, who has campaigned to change the flag, said the wider the debate, the more likely the mood for change.

"The more engagement, the more likely they are to want a switch to an alternative. People become more and more informed and less and less narrow in their views, and what will become increasingly debated is what the alternative could be."

Contradictorily, asked if the present flag was distinctive enough, 54 per cent of those in the Herald survey thought it was, and three in five said they would keep the Union Jack in a new flag design.

The greatest proportion of supporters wanting to keep the Union Jack came from young adults: 73 per cent of 18- to 24-year-olds and 74 per cent of 25- to 29-year-olds.

The 18-to-24 age group also showed higher support for the present flag (61 per cent), second only to the over-70 age group (63 per cent).

Those outside the Herald's main area, Auckland, had less conservative views, with 52 per cent saying the present flag was good enough, compared with 57 per cent in Auckland.

Only 48 per cent of Aucklanders thought it was time to change the flag, compared to 55 per cent of the rest of the country. Only two in five Aucklanders supported the silver fern as an alternative design, significantly less than the rest of the country (59 per cent).

And far more Aucklanders - one in four - backed the koru than the rest of the country (15 per cent).

Mr Morrison said it was odd that young adults showed the most support for keeping the Union Jack in a new design. "I don't see any logic in keeping the Union Jack over a period of time. That's someone else's flag."

The poll canvassed 600 respondents between January 29 and February 10, and has a margin of error of 4 per cent.