Api to be here: Back-up Blue ready for any scenario

Api Koroisau can't be sure he'll get on the field in next Wednesday's Ampol State of Origin series opener but he is content to miss selection for Penrith and play a role for the Blues should he be required.

The livewire Panthers dummy half is 18th man for the Blues in Townsville, which means he won't be available for the depleted Panthers in their quest to remain unbeaten on Friday night.

Panthers coach Ivan Cleary delivered Koroisau his selection news on Sunday morning before mapping out his own plan to fill seven vacant spots for the clash with Wests Tigers at Leichhardt Oval.

Cleary will likely turn to Mitch Kenny to replace Koroisau at hooker.

"It's a tricky situation to be in, especially knowing we've got so many Panthers boys not playing, but also the camp itself is easy to come into, regardless of how we're travelling," Koroisau told NRL.com.

"It's one of those opportunities you take with both hands. Ivan spoke to me about not being able to play this Friday so I've known that was the arrangement as soon as I came into camp and I am OK with that."

NSW coach Brad Fittler told NRL.com on Monday he gave Koroisau the role as cover for Damien Cook in case anything happened to the starting hooker.

The only way Koroisau will get on the field in Origin I is if three players fail HIAs during the match, or a player is ruled out through an act of foul play that results in a Maroons player being sin-binned or sent off.

"You don't want anyone to get hurt or to get on the field like that but the role has changed quite a bit over the last few months," Koroisau said.

"You never know what the chances are of getting out there so you've just got to prepare like you're going to play and be ready.

"Personally, whether I play or not, I'm just looking forward to the deafening roar. It's what I'm imagining at the moment and I'm up for that."

Koroisau is one of six players in the NSW squad who has international experience for other nations including Fiji, Samoa and Italy.

Panthers five-eighth Jarome Luai has represented Samoa on five occasions, while Koroisau is a Fijian veteran with 16 Test caps since 2013.

Tariq Sims (Fiji), Daniel Saifiti (Fiji), Junior Paulo (Samoa) and James Tedesco (Italy) have also played for other countries previously.

State of Origin eligibility rules have tightened in recent times but players have the flexibility of playing for their states they were either born or played their junior rugby league in.

"I'm a very proud Fijian and I'd love to keep that connection with my culture any time I can but I was born and played my junior rugby league in Sydney and I'm a Blue through and through," Koroisau said.

"A lot of the boys are born here and have grown up their whole lives here. To be able to represent your culture as well it's awesome to be able to have that mix.

"They're the games during the year where everyone bunkers down and gets around the TV.

"I wasn't a big footy fan growing up but you always watched Origin, no matter where you lived."