Both flags have Union Jacks reflecting that both were once British colonies. The Australian flag features the Commonwealth Star; the New Zealand flag does not. In its’ Southern Cross, the Australian flag has four seven pointed stars and another one with five; the New Zealand Flag has four five pointed stars. The Southern Cross in the Australian flag is white whereas it’s red with white border in the New Zealand flag.
The three colours speak to us of the Trinity; Red, the Son. White, the Holy Spirit. Blue; the Father. Three Persons, but one GOD. Red. the colour of blood, signifies Justice or Judgment, and reminds us of the life laid down of the Son of God.  White signifies Purity or Holiness. God calls His people to be a holy people. Blue, the colour of the sky, signifies Love, the Home of God, and our home when washed in the Blood of Christ.