Tonga mounted sustained pressure as Dallin Watene-Zelezniak was stopped heavily on the 10-metre line while bringing the ball back for a second hit-up.
Junior Paulo delivered the challenge, prompting a brief push and shove between the players. The referee awarded Tonga a penalty for the tackle.
Watene-Zelezniak appeared to have crossed the line less than a minute later, but the winger had stepped into touch and the try was ruled out without a referral to the bunker.
Tonga were handed another opportunity when Chanel Harris-Tavita kicked the ball out on the full from about 42 metres from his own line. However, Robert Toia then lost possession less than half a metre from the tryline, leaving Tonga threatening but still without the opening points.
