The current New Zealand flag and the contender to replace it will be flown together in 280 locations across the country.
The idea is to allow people to see them together in real-life situations before the final referendum in March.
The Silver Fern flag design by Kyle Lockwood was chosen in an earlier referendum for the final referendum where it's pitted against the existing flag.
Flag Consideration Panel chair, Professor John Burrows, said that whether the flag changes or not is a very personal decision, and an historic one.
A video on the symbols, colours and meaning of both flags is available on the panel's website, as is a letter summarising some of the most commonly expressed views that have been shared.
The two flags are flying on the Auckland Harbour Bridge until March 24, with the exception of Waitangi Day when the current New Zealand Flag will be flown with the Tino Rangatiratanga flag.
The referendum runs from March 3 to March 24.