New Zealanders are adopting the Silver Fern as the national flag because they identify with it more than the Southern Cross, a leader for a republican movement claims.
Flag campaigner Lewis Holden said New Zealand needed a flag that Kiwis connected with and related to, rather than one which gets confused with the Australian flag.
"It's important that we talk about this on our national holiday, these issues of symbolism. Because it is actually quite important, feeling like you're part of something," he said.
Mr Holden, chairman of the Republican Movement of Aotearoa New Zealand, was involved in the 2005 campaign to hold a referendum for a new flag.
The petition attracted about 100,000 of the 270,000 signatures required for the referendum to be considered by the Government.
Mr Holden said it was evident at sports matches and events of national significance that New Zealanders preferred to wave the Silver Fern.
"And from pictures I've seen of the Waitangi Day pub crawl in London, very few people actually had New Zealand flags - they were all draped in Silver Ferns or Southern Crosses."
Labour spokesman for Arts, Culture & Heritage, Charles Chauvel, who put forward the New Zealand Flag Bill in 2010, said the Government needed to address the issue.
"We should be able to openly debate who we are as New Zealanders, as a Pacific nation, but also one filled with many other cultures."
Mr Chauvel's bill, which is waiting to be drawn, seeks to create a commission which must spend 18 months seeking public input on the status of the national flag.
The commission would be appointed by the Prime Minister after consulting all parliamentary leaders.
As part of its functions, it would hold a nationwide competition for new flag designs, ranking the three that best reflect national identity, aspirations, culture and heritage.
It also advocates flying the current flag at occasions within New Zealand, but to use the new flag overseas.
Mr Chauvel said it was time to address the national identity.
In a 2010 Herald survey of 18 of the 22 members of the Order of New Zealand, 11 believed it was time for a new flag. Five opposed a change, one was unsure and one was unwilling to comment.