The Sydney Morning Herald and Daily Telegraph have both reported that drug testers visited Newcastle on Tuesday at the request of the NRL integrity unit, which is investigating the incident at the Hotel Delany on Saturday night, when both Ponga and Mann were removed from a toilet cubicle by a security guard.

Reports indicated the pair were required to submit urine samples, as opposed to undergoing hair-follicle testing, a more thorough process that can detect illicit substances months after they have been consumed.

It is understood that if players test positive to drugs, clubs are under no obligation to make those findings public.

Newcastle's new director of football, Peter Parr, was asked at a media conference on Tuesday about speculation surrounding possible drug use and replied that he was keeping an "open mind on the whole situation".

"The indications to me is that didn't happen, so I have to be confident that's the case," Parr said.

At the very least, Ponga and Mann were drinking alcohol while they unavailable to play because of injuries.

Ponga has missed the past three games and won't play again this season after a spate of concussions.

Mann has been sidelined for more than a month with a torn quadriceps.

Clubs generally prohibit their players from consuming alcohol while injured because it inhibits the healing process.

Ponga's father, Andre, suggested to News Corp on Monday that his son and Mann were in the cubicle because Newcastle's skipper was under the weather.

"He made an exciting house purchase Saturday and celebrated with a few mates drinking," Ponga senior was quoted as saying.

"Sick in the toilet and his mate went in to help him."

Parr said on Tuesday that incident was "not a good look" for the club but there had been "no direction given to Kalyn [from his neurologists] that he shouldn't drink".

There have been widespread calls for Ponga to be stripped of the club captaincy, and Parr acknowledged a "lack of leadership" was an issue Knights management needed to address.

WHAT DO YOU THINK? We've made it a whole lot easier for you to have your say. Our new comment platform requires only one log-in to access articles and to join the discussion on the Newcastle Herald website. Find out how to register so you can enjoy civil, friendly and engaging discussions. Sign up for a subscription here.