Downing St said it had made no preparations for a yes vote - including on the question of the national symbol.
A spokeswoman from the office of Prime Minister John Key, who earlier this year said consideration of a new flag would begin after this year's election, said as Scotland's independence referendum had not been completed and the result was unknown it was too early to comment on what effect secession would have on a change of flag here.
"It's a matter for the people of Scotland to decide and it would be inappropriate for the Prime Minister to comment on matters relating to the referendum ahead of a result being known," the spokeswoman said.
"Earlier this year, the Prime Minister outlined a plan for considering a change in the New Zealand flag. That plan has not changed."
Mr Key has outlined a plan for a cross-party group of MPs to recommend the best process for referenda on the flag, and a steering group to ensure the public has the opportunity to engage in discussion on the flag, and to submit design ideas.
Senior researcher at Massey University Malcolm Mulholland said because New Zealand, like several other countries, incorporates the Union Jack in its flag a discussion around it would have to happen if Scotland did secede.
"You would have what we know as the Union Jack missing from your flag, I would think that would have to happen and the New Zealand Ensign Act, I would imagine, would have to be amended to reflect that."
Ministry of Culture and Heritage spokesman Sean McKenna said if Scotland became independent, the UK may consider changing the Union Jack but this "would not happen quickly".
"Again, this consideration process would likely take some time, and the New Zealand Government would look at what other countries were doing.
"This is all very conditional and at each step time would be needed to work through the issues."
Earlier this year a Herald-Digipoll survey revealed a majority of New Zealanders were against changing the national flag but if a new flag was chosen in a public referendum, the silver fern was the most popular design.
Asked if they felt the time had come for New Zealand to design a new flag for itself, 52.6 per cent of those surveyed said "No" and 40.6 per cent said "Yes".
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