"I'm gutted but I don't really show emotion in terms of that - I'll probably go home and cry my little eyes out in my room.
"I'm sad for the team but I'm also really proud of how far they've come on this journey.
"They've done really well.
The Tony Benson-coached side enjoyed the better run of play for much of the game but Australia capitalised on their chances in the second-half to build out to a 22-10 lead.
New Zealand came back with a try to five-eighth Raecene McGregor to give them hope in the last 10 minutes before Australia clinched the result with halfback Caitlin Moran nailing a field goal in the last minute.
"We hung on there, a couple of errors and penalties let us down but it was just one of those games," she said.
"It was a hard-fought battle right to the end and unfortunately we didn't t the result we wanted."
Mariu is encouraged by the NRL's plans to establish a Women's competition and hopes New Zealand rugby league can develop further either by potentially having a Warriors side involved or Kiwi players winning contracts with Australian clubs.
"I haven't really thought about myself but I'm happy that their potentially could be a women's competition in the NRL, she said.
"From this World Cup, the exposure we've gained is going to be setting the pathway for our young people."
