A New Zealand First MP has used tonight's urgent reading of a bill to include Red Peak in the flag referendum, to draw attention to what he says are similarities to Nazi war symbols.

Parliament has been working under urgency tonight to get the Red Peak design into the November referendum as a fifth option.

Denis O'Rourke says Red Peak flag is too similar to markings used to paint Nazi sentry boxes.

He held up a picture of a Nazi sentry box, saying: "Look at the fact that it begins with a red peak with a white peak on top of that also identical to the red peak flag...and then a black peak on top of that also identical to the Red Peak flag. Only that little bit of blue in the corner is missing. There is an uncanny resemblance.

"And the sad fact is the Nazi colours were red, white and black as the Red Peak flag is."

The NZ First MP then held up a picture of a Nazi sentry box and the Red Peak flag side by side, saying the similarity couldn't be much closer.

He also held up a picture of the Red Peak flag turned into a Nazi swastika, saying he found it online and New Zealand will be "ridiculed" overseas if the country was to adopt "that kind of awful monstrosity of a design for the New Zealand flag".

The Greens proposed the bill allowing a fifth flag in the referendum, with no conditions as Labour had demanded. Labour wanted a "yes" or "no" vote to change the flag first.