That could be with a fist or arm, including the elbow, shoulder, head or knee. Players are also not allowed to stamp, trample, kick or trip an opponent either.
Regardless of the strength and power of the contact Quirk made, by the letter of the law, there was nothing else O'Keeffe could have done.
On the flip side, Chiefs midfielder Johnny Fa'auli's red card against the Hurricanes last night was more clear cut.
Fa'auli was sent off during the second half in Hamilton for a dangerous tackle on Wes Goosen.
Johnny Fa'auli is given a red card. Photo / Getty Images
The high, no-arms shot on Goosen fired up Hurricanes head coach Chris Boyd who called it "deliberate" and Barrett agreed that it didn't look good.
"It was pretty reckless … it's a shame because Goose might be out for a few weeks, he was pretty sore after that," Barrett said.
All Blacks coach Steve Hansen has previously shared his views on how the game is being officiated, stating that common sense needs to prevail.
Hansen says the referees aren't to blame and that they're just doing their job, but World Rugby's laws need to change to allow a more common sense approach.
"It's become plainly obvious for everyone to see now. Nothing's changed in a year - that is a fact. Something will change in the next few weeks," Hansen said.
"It's a birds nest and it'll take a bit of tidying."
