The 24-year-old was a notable omission from the Tonga squad announced last week, given his devastating abilities as a broken-play runner at either wing or on the flank, but Taione's continuing presence in England during October and November will be a major plus for the North East club.
"It took me a while to make the decision," Taione told the Newcastle Journal.
"It's a shame and I don't think it went down too well in Tonga, but I told them I had my family to look after and I wanted to concentrate on this coming season with Newcastle.
"It's every player's ambition to play in the World Cup but I weighed up everything and decided I couldn't commit to it this time around. I played in the last World Cup when I was one of the younger players and I know the selectors were hoping I would play a more senior role this time around.
"But I don't want another season like the last where I had injuries, struggled with my form and there were question marks about my future with the club. I want to dig in and make sure I get back to my best."