Queensland reject speculation surrounding Billy Slater's fitness

Queensland may have shot down speculation Moses Mbye is on standby for Billy Slater as 18th man but Maroons flyer Dane Gagai believes the Canterbury fullback is ready for State of Origin.

Eyebrows were raised when reports claimed Mbye would be called into Camp Maroon with a question mark over veteran No.1 Slater (hamstring) ahead of the June 6 series opener.

Queensland officials said Mbye would join the Maroons squad on Thursday - as one of six development players.

Mbye and five others have been invited to train with the squad on Thursday and Friday at their Gold Coast camp.

Moses Mbye has been called into Maroons camp.

Brisbane's Joe Ofahengaue is believed to be Queensland's official 18th man.

Gagai backed Slater to play his 30th Origin and run out with the Maroons' other concerns - lock Josh McGuire (ankle), halfback Ben Hunt (thigh) and bench utility Michael Morgan (sternum).

All four missed Tuesday's opening training session.

Queensland next train on Thursday on the Gold Coast after relocating from Brisbane to Sanctuary Cove on Wednesday.

Gagai said Slater sounded determined to play after announcing he would retire from representative football after the 2018 Origin series.

"Knowing Billy, he will be fine," Gagai said.

Slater missed the Maroons opening training session.

But Queensland winger Gagai believed it was a matter of time before Wests Tigers recruit Mbye donned Maroon.

Mbye is considered a contender for the Maroons No.1 jersey along with Brisbane skipper Darius Boyd and Newcastle's hot favourite Kalyn Ponga when Slater walks away from Origin.

"I think he has all the attributes (for Origin). He can play in the halves, at fullback," Gagai said.

'I think his tackle breaks and running metres are right up there, he's evasive and has skill as well.

"I think (coach) Kevvie (Walters) is just bringing him in to train with us along with some others, just to get that feel for it so if that opportunity ever came along he doesn't get chucked in the deep end.

"But I think he would be able to handle the occasion."