Tolu Latu's World Cup selection prospects are in tatters and the Waratahs' already controversial season took another hit over Rugby Australia's probe into the hooker for an alleged drink driving offence.

Latu failed to inform the Waratahs of the incident, which threatened to derail their fighting 40-32 win against the Queensland Reds at Brisbane's Suncorp Stadium on Saturday.

In the wake of Wallabies star Israel Folau's sacking, the incident was a public embarrassment the club could ill afford as it scrapped to keep its season alive.

Yet thanks to the reliable boot of Bernard Foley, some desperate tryline defence and some late scrum victories against the Reds pack, the Waratahs have moved back to within a win of the top of the Australian conference.

"To get over in a tight one was nice," captain Michael Hooper said.

"It's been all too familiar looking up at the clock at 70 minutes and the game's in the balance. It feels like that for most of our games this year."

Latu faces an investigation by the code's Integrity Unit after being charged for an alleged drink driving offence.

The Daily Telegraph reported that the fringe World Cup contender had returned a blood alcohol reading of 0.135 early on Thursday morning.

He was not stood down from the win against the Reds, but Rugby Australia has discretionary powers under its professional players' code of conduct to sideline the former Wallaby until the investigation is complete.

Amid all the drama, NSW found a way to win despite conceding six tries to four in the interstate clash.

Sekope Kepu drove Reds prop JP Smith back to save a try while winger Cam Clark chased down and burrowed under a tryline-bound Alex Mafi in a sign that what doesn't kill the side can make them stronger.

And just seconds after missing a tackle to allow a try, halfback Nick Phipps charged down a Bryce Hegarty conversion attempt to save two points.

"It speaks volumes, the desperation of Cam Clark to get back," coach Daryl Gibson said.

"All year, I've said this team fights. It's a hallmark of this team.

"I wish it didn't have to all the time. We've put ourselves in positions where we've had to and of course I'm very proud of that."

A win at home against the Jaguares next Saturday would give Gibson's team a shot at topping the Australian conference.

The Reds remain a slim finals chance but fresh injury concerns over Chris Feauai-Sautia (knee), JP Smith (concussion) and Caleb Timu (concussion) could severely weaken their prospects on Friday against the Chiefs.

Australian Associated Press