UPDATED 2.50PM: Prime Minister John Key is urging people to put politics and personalities aside when they come to voting over the coming weeks for which flag they'd like New Zealanders to fly in the future.

The Electoral Commission is sending out voting papers today and people will have until March 24th to choose between the existing 'Southern Cross' flag and Kyle Lockwood's 'Silver Fern' design. 

Key hopes voters will take the once in a lifetime opportunity to have their say and forget the politics.

"Some people have politicised it, you know I can lament that all I like, but that's politics, it's the big bad world we're in."

"In the end, New Zealanders will decide which flag they want, whatever flag they choose I'll respect them."

The Greens however dismiss the "once in a lifetime opportunity" claim as propaganda.

The party's co-leader Metiria Turei said we can have another at go the flag, at any time.

Ms Turei said she's considering either voting for the old flag or not voting at all, because she doesn't believe the alternative is the right one for the country.

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Key said if people don't vote because they don't like him then they're simply wasting their vote.

"That's not the deciding factor here. The deciding factor is which flag do you want to represent the country, hopefully they'll chose the one that they think is best."

ACT Leader David Seymour is not in the Prime Minister's corner when it comes to changing the flag.

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Mr Seymour said he will be voting to keep our current flag, saying the concept of change is not a bad one, but the alternative design is far too aesthetically confused.

"It will date rapidly, and we'll look back on it in 30 years time the same way that we look at corporate logos now."

Green Party co-leader James Shaw has also given his take, saying he doesn't favour the Lockwood design.

"I don't think it efficiently tells the story of who we are as a nation, and so I'll be voting to keep the existing flag on this occasion."

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And Labour MP David Parker said he will also stick with the status quo.

"I'm voting for the existing flag, not the bath towel," he said.

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An Australian endorsement for New Zealanders to change our flag, isn't getting the warmest reception from Key.

The group Ausflag has taken out an ad in the New Zealand Herald, urging voters to take advantage of a once in a lifetime opportunity to end the confusion with Australia's flag.

John Key said most New Zealanders are capable of making up their own minds.