Rugby league great Jonathan Thurston says he is concerned for the well-being of former teammate James Segeyaro after the off-contract Brisbane hooker tested positive to a banned substance.

Segeyaro has been temporarily suspended by the NRL after he returned a positive A-sample for Ligandrol, a non-steroid anabolic agent popular with bodybuilders.

The NRL said in a statement on Thursday that Segeyaro was tested by the Australian Sports Anti Doping Authority on September 3rd.

Thurston, who played with Segeyaro at North Queensland, is concerned for the mental health of the nine-year veteran.

"First and foremost we need to check on his wellbeing," Thurston told reporters in Sydney on Friday.

"He'd just started to get his football back in check with the Broncos and this is a huge blow to him.

"Hopefully he's getting all the help that he needs. It's not a great look for the game."

The RLPA has organised independent legal representation for Segeyaro who is currently on holidays in Europe.

Due to the temporary ban, it seems likely that Segeyaro will be unable to represent Papua New Guinea at this month's World Cup Nines tournament after being named in their squad this week.