The New Zealand flag referendum has opened - in a move which could see the end of the Union Jack on the national flag.

Voters have until December 11th to submit their postal ballots choosing between five new designs. The winning design will then go head-to-head with the current one.

Three show variations on the silver fern, while a fourth - 'Koru' - is a Maori symbol representing life, growth, strength and peace.

The fifth design - Red Peak - was designed by Wellington man Aaron Dustin, and included in the long list of flags submitted by members of the public. However it failed to find favour with the flag committee who selected the top four.

The design then became popular with New Zealanders, and nearly 52,000 people signed a petition to have it included in the vote.

Prime Minister John Key agreed to have Red Peak added after the calls for its inclusion.

Voters will choose between the current flag and the most popular new design in a second referendum to be held next March.

Mr Key says it is too soon to pick which way it will go:

These people in Wellington have been reacting to the current referendum, suggesting it should be part of a larger debate: