Prime Minister John Key says few people waved the New Zealand flag at the Bledisloe Cup match against Australia last week because it was too similar to Australia's flag.
The controversial $26 million flag referendum has been mired in debate, but Mr Key is front-footing the issue with an opinion piece published in newspapers today.
He says there was a "sea of black" at the rugby decider at Eden Park last Saturday night but very few New Zealand flags in the crowd.
Most New Zealanders do not think of the flag as their preferred way to display their sense of national identity, he says.
"Besides, it's too much like Australia's, especially when New Zealand is playing against Australia.
"Without being able to count the stars, how would people know whose flag anyone was holding?"
He says changing the flag would not disrespect the New Zealand servicemen and women who served under it.
"Last Saturday night I wore a New Zealand Rugby Union tie with a silver fern on it. On my lapel I also wore a silver fern because it, to me, symbolises this country that I love and so proudly serve," he says.
The Flag Consideration Panel has narrowed down more than 10,000 submitted designs for a new New Zealand flag to 40.
The Union Jack isn't on any of the 40 designs.
WHERE TO FROM HERE FOR A NEW FLAG?