Jason Momoa has called for a ''proper investigation'' into allegations of misconduct on the set of 'Justice League'.

The 41-year-old actor has spoken up in support of Ray Fisher, who claimed in July that director Joss Whedon ''was gross, abusive, unprofessional, and completely unacceptable'' while shooting the 2017 blockbuster and had been ''enabled, in many ways'' by then-DC Entertainment President and Chief Creative Officer Geoff Johns and producer Jon Berg.

And the 33-year-old actor's co-star has spoken up and claimed the cast were treated in a ''s***'' way while working on reshoots for the filmmaker, who took over as director from Zack Snyder when he stepped down for personal reasons.

Jason shared a photo of himself and Ray on Instagram and wrote: ''THIS S*** HAS TO STOP AND NEEDS TO BE LOOKED AT. @ray8fisher AND EVERYONE ELSE WHO EXPERIENCED WHAT HAPPEN UNDER THE WATCH OF @wbpictures NEEDS PROPER INVESTIGATION.(sic)''

The 'Aquaman' star then branded a news report that he was in talks to voice Frosty the Snowman in a movie ''fake'' and suggested it was only released to draw attention away from Ray's claims, as it was published on the same day his pal - who portrayed Cyborg - came forward.

He wrote: ''I just think it's f***** up that people released a fake Frosty announcement without my permission to try to distract from Ray Fisher speaking up about the s*** way we were treated on Justice League reshoots.

''Serious stuff went down. It needs to be investigated and people need to be held accountable. #IStandWithRayFisher. aloha j.(sic)''

Jason's comments came shortly after Ray claimed Warner Bros. had failed to speak to ''key witnesses'' in their investigation of his allegations.

He tweeted: ''To-date, the 'independent' firm hired by @wbpictures has conveniently avoided contacting key witnesses who gave damning statements to WB HR.

''They've also started interviews with (and have since ghosted) witnesses that have implicated former and current top level executives.

''Others (including an implicated individual that called me to apologize) have already been interviewed. We will not let ANY investigator cherry-pick interviewees that best suit @wbpictures' false narrative and scapegoating efforts. All with stories WILL be heard! A>E.(sic)''

Neither Ray nor Jason have given specific details on the allegations.