Originally Posted By: LukeJavan8
And more in the article containing the aforementioned
5 national flags:

http://www.teara.govt.nz/en/southern-cross/1

which lists several more!

Flags that fly the Southern Cross

Depicted either as four or five stars, the Southern Cross features on the national flags of New Zealand, Australia, Brazil, Papua New Guinea and Samoa. It also appears on the Australian flags of Victoria, Australian Capital Territory and Northern Territory, and on the flag of Chile’s Magallanes region. The flag of the Southern Common Market, the South American trading bloc of Argentina, Brazil, Paraguay and Uruguay, also depicts the constellation.