Katoa said visa processing times and logistical challenges of getting his mother Akanesi to Sydney in time for Sunday's clash with Brisbane had proved too hard a task.
The 25-year-old hails from a village called Koulo on the island of Lifuka, 200km away from the Pacific nation's capital of Nuku'alofa.
Katoa has previously credited his mother as being his biggest influence after the death of his father when he was just 12.
"Unfortunately mum can't make it, but I do have a few family members coming from New Zealand and a cousin who's coming from America," he told AAP.
"I'm very grateful they'll be there but mum's stuck at home. I think I'll go back home as soon as the season finishes.
"There's a couple of things that I needed to do for her to come over here and I haven't done that but hopefully one day she'll get to see me in a grand final.
"I've got a few messages from (family in Koulo) and they're very proud and excited and they are going to get together and watch the grand final together."
Back-rower Katoa, who was named in the Dally M team of the year earlier this week after scoring 13 tries in 25 games, was part of the Storm side that fell to Penrith in last season's decider.
"We've been here last year and came up short, but I feel like we've been building to this," Katoa said.
"I feel like the emotion within the group, everyone understands that feeling from last year and we don't want to have that feeling again.
"But we also don't want to really think about it too much because we have a different team."
Katoa singled out front-rower Stefano Utoikamanu for helping propel Melbourne into premiership contention with his late-season form.
The usually mild-mannered Utoikamanu has shown no fear of Brisbane this week, labelling Broncos players as "stuck up".
"He's been amazing and I feel like after the Origin period he came back and he's been a different beast," Katoa said.
"We know he's got that in him and I feel like he has been going good for us and we will need another big game from him on Sunday.
"He doesn't really say a lot, but whatever he says I've got his back."
