Papalii, who played for Samoa at the 2017 edition before representing Australia since, joins Penrith guns Brian To'o and Jarome Luai as the biggest names to pledge they'll represent their families' heritage at the tournament.

The veteran front-rower said he's already told Kangaroos coach Mal Meninga of his decision, although he's yet to inform Samoa coach Matt Parish.

But Parish will hardly say no to the 30-year-old, who along with To'o and Luai will add to an already-impressive side that beat Cook Islands 42-12 in June's Pacific Test.

Papalii said he felt a responsibility as a senior player to lead the way and represent his "motherland".

"As an older player, I feel like it's a movement I just don't want to be missing out on," he told reporters on Wednesday.

"Just seeing the likes of a few of the Penrith boys coming out and I've had few text messages from other players who haven't come out yet saying they've put their hand up for Samoa.

"I have put my hand up to play for Samoa. Mal Meninga knows that and I've had a coffee with Mal as well to speak about what I'm planning to do ... but that's a long way from here, anything can happen in the next hopefully eight weeks."

Papalii showed pride for his heritage after Queensland's State of Origin win, posing behind the Samoan flag with other potential representatives Tino Fa'asuamaleaui and Jeremiah Nanai.

He admitted he wasn't at his best when with the Samoa side at the 2017 World Cup and vowed to make amends for his side's winless effort.

"I guess probably my last World Cup wasn't the best, I sort of treated it as a little vacation and probably drank a bit too often, ate more than I should have," he said.

"I'm looking to just play a bit of World Cup for the Motherland and represent my wife and my kids and especially my parents as well and just make Samoa proud."

Australian Associated Press