National teams are expected to name their final 23-man World Cup squads on Monday, leaving several eligible players facing imminent decisions.
Robert Toia has told Tonga he intends to represent them, although Australia coach Kevin Walters says the Sydney Roosters centre remains available to Australia.
Toia has played six matches for Queensland and represented Tonga once at last year's Pacific Championships before injury.
Tonga coach Kristian Woolf told AAP, "All three of those players have told me that they are available to play for Tonga at the World Cup."
He was referring to Toia and Gold Coast backs Jojo and David Fifita, who AAP understands were named in the initial 40-player squads of both nations.
Jojo, who has Tonga, New Zealand and Australian heritage, said he had spoken with all three countries but had not chosen which to represent.
"I haven't made a decision yet but it is coming closer. I will know in the next couple of days," he told AAP.
He has played State of Origin for Queensland but is yet to make his Test debut; his father, Pila, represented Tonga in rugby union.
David played four Tests for Tonga at the 2022 World Cup, while Walters said both brothers were being considered by Australia for 2026.
Walters also identified Brisbane centre Kotoni Staggs as a contender, citing his performance on the Ashes tour.