Haas, Gold Coast captain Tino Fa'asuamaleaui and Dolphins fullback Hamiso Tabuai-Fidow have all represented Australia but will soon make a decision about whether they link with Samoa for the end-of-season Pacific Championships.
The tournament is on at the same time as the Kangaroos' three-Test tour of England.
Carrigan was asked if he hoped Haas chose Australia.
"I'd hope so, as a fan I'll line him up for us and cheer him on," he said.
"Him and (Kevin Walters) have got a good relationship so I'm sure Kev will get into the big fella's ears."
Carrigan wants the best Australian team possible to tour but understands if Haas, Fa'asuamaleaui and Tabuai-Fidow honour a part of  their heritage that is dear to their hearts.
"Everyone has different cultural backgrounds and family experiences," he said.
"My love to play for Australia and for my country comes from my parents and their hard work so if those boys feel passionate about representing Pacific Island nations or little countries then so be it, that's their choice and I think it makes for a better product.
"I don't begrudge them at all."
It is a balancing act that Carrigan said the international game had got right after Samoa made the last World Cup final.
"They're elite players in the Australian competition in our game so you want them playing for Australia, but I love where the international game is going," Carrigan said.
"The boys represent their culture and their family and gone are the days where you had semi-finals in World Cups where someone was winning by 70 points.
"That's where rugby league should be and I think it's only better for our international game if the best players are playing for who they want to play for."
The next World Cup will be hosted by Australia and Papua New Guinea next year,
If Walters succeeds on the Kangaroo tour he will be a hot favourite to retain the position.
Carrigan was coached for four seasons at the Broncos by Walters and said he would make an ideal coach of the national side.
"His personality, his charisma, his passion for any jersey that he's ever worn and especially for his country would be massive," Carrigan said.
"He knows how to bring the best out in a wide magnitude of players from different backgrounds."
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