"We need any and all support to take him home from Brisbane, back to New Zealand. Our goal includes funeral expenses and travel expenses for his family."
Paul said the family wanted to provide more depth and details of James' death "once more becomes clear to us".
"It's hard having to reach out for help, but all we can say is that any help big or small is more than appreciated."
By 2.30pm yesterday the page had received $7050 in donations.
Paul expressed her heartbreak on Facebook, paying tribute to her brother with a photo and post that questioned if it was all "just a dream".
"Brother, I can never be the same without you. How can I ever possibly heal a wound that I can't see, how am I meant to stop this wave of emptiness."
James' cousin, K Tamihana Hunter, also took to social media to express his deep grief, saying he would look after James' sons like they were his own.
"Can't describe this pain my cuzzy since I could remember we would always have that bond no one would even know."
Police were called to a property north of Brisbane about 5.15pm where they found two men with gunshot wounds. The men were taken to hospital but both were pronounced dead.
Witnesses told police a man was allegedly seen fleeing the area shortly after, 9News reported.
"I was in my bedroom and not long after 5pm there were two gunshots," neighbour Calise Ryan said.
Another neighbour, Morgan Blake, told 9News: "One of my neighbours pulled up and said 'Some guy has been shot ... running around with a gun."
The two victims were James and a 37-year-old man who has not been named, 9News reported.
Some of those who donated to the family's cause said they knew or remembered James and described him as "cheeky" and "always smiling".
Police arrested a 24-year-old at a service station later that night and charged him with two counts of murder, possession of a shortened firearm, unlawful possession of weapons and authority required to possess explosives, 9News reported.
The Daily Mail reported Detective Superintendent Ben Fadian said James lived at the address and the three men were known to each other.
Police were still trying to establish a motive for the shooting, Daily Mail reported.