Riera says he has talked to Hudson "every now and again".
"He has said he would be happy to have me in the squad but there is nothing I can do or he can do," said Riera. "Someone else needs to look at it. "
Riera, who arrived here on a working holiday visa more than five years ago, said it would be a dream come true to turn out for his adopted nation.
"It would be a great opportunity to give back from everything I have received from this country. I'm very glad for all the experiences I have had."
Riera, who left the Wellington Phoenix at the end of last season, has another chance to remind of his value on Thursday night. With the loss of Te Atawhai Hudson-Wihongi, and Mario Bilen in doubt, Riera will need all his experience and guile in midfield against the J League champions.
It will be his third Club World Cup, after narrow losses to Kashiwa Reysol (1-0) and Sanfrecce Hiroshima in 2011 and 2012 respectively.
"I think this year we are well prepared," said Riera. "Every year Auckland City is getting stronger and stronger so we are increasing the chances to beat them."
But the gulf in class remains huge. It's hard to compare with other scenarios, but in terms of resources, it's a bit like a non-league team taking on Chelsea or Liverpool in the FA Cup. Anything is possible, but Auckland City will need the perfect storm of circumstances on Thursday.
"It's a massive gap, but pretty much everyone in this squad has already played in this tournament and we have to use that," said Riera. "It's almost like overnight we have to step up to that high level.
As always, the Auckland City players won't lack for preparation, as coach Ramon Tribulietx has compiled lengthy dossiers on their possible opponents: Urawa Reds or Kashima Antlers.
"Ramon has been studying the other clubs for a long time," said Riera. "We don't want any surprises and you have to be very prepared, especially to be competitive."
And, just like in 2009 and 2014, when the Sandringham club captured the imagination of the footballing public with improbable Club World Cup runs, Auckland City have nothing to lose.
"It's one game -- like a final," said Riera. "We want to enjoy it and try to be competitive."