Oita - Wallaby coach Michael Cheika said his side's ill-discipline and slow starts were becoming a problem after two yellow cards in their 45-10 win over Uruguay on Saturday.

With a likely quarter-final looming against England, captain Michael Hooper also said the Wallabies were making it hard for themselves with their high infringement rate.

They spent half the first spell against Uruguay down to 14 men with Adam Coleman and Lukhan Salakaia-Loto sin-binned for head-high tackles, while Hooper and Kurtley Beale were also penalised for high shots.

In the Pool D match in Oita, which the Australians were expected to win comfortably, they gave away 12 penalties to take their total to 35 from three matches.

"Discipline in general," Hooper said, when questioned about key issues facing his side as they move closer to the knock-out stages.

"A bit of high-tackle stuff, it's a bit of offside line. Giving away as many penalties as we did today made it hard for ourselves, particularly having 14 men on the field for 20 minutes.

"It's hard, it makes life hard, it takes a lot of energy out of the tank."

Discipline has been an ongoing concern for the Wallabies in Japan, with Cheika initially defending his side by saying he was "embarrassed" by the confusion around officiating high tackles, the subject of a new referees' 'framework' to guide punishments.

"We don't need the framework to teach us where to tackle because they are all taught to tackle middle," he said, after Reece Hodge received a three-match suspension for a dangerous tackle in their opening match against Fiji.

But after the high shots against Uruguay, Cheika refused to discuss tackle technique. "I think it's pretty clear why not, just steer clear of it and everyone will be good," he said.

He said the bigger problem was the total penalty count, linking it to the slow starts which also troubled the Wallabies in their first two matches when they beat Fiji 39-21 and lost to Wales 29-25.

"We're just giving away too many penalties, full stop, no matter what it's for," Cheika said.

"You can't be winning the game by 45 and still losing the penalty count. We've got to stop giving away penalties."

He suggested a possible link between infringements and a lack of playing cohesion at the start of the game.

The Wallabies were only 19-3 ahead at half-time after spending much of the first half defending, before producing a more complete performance after the break.

"The one thing we need to be mindful of is we haven't started games well, not that we haven't played well, we've just been a little less consistent in the first 20 minutes," he said.

"It gets you off on the wrong foot and it's definitely something we need to address. When we get our flow going we give away less penalties."

Coleman received his yellow card for in the 14th minute and Salakaia-Loto was sent off 15 minutes later.