Robin McBryde says Wales' players are fully aware of the potential sanctions for any disciplinary lapses during the World Cup.
Australia wing Reece Hodge will miss Sunday's Pool D showdown against Wales after receiving a three-match ban for a dangerous tackle.
Two Samoa players – Rey Lee-Lo and Motu Matu'u – are awaiting disciplinary hearings following citings for dangerous tackles during the victory over Russia on Tuesday.
"We will have to be on the money straight from the off and expect the unexpected."@George_North and @dillon3_ say Wales are ready to step up another level against Australia this Sunday in #RWCTokyo https://t.co/R44wS5puHd #WALvAUS pic.twitter.com/9ibRL0VHNM — Welsh Rugby Union 🏉 (@WelshRugbyUnion) September 26, 2019
Both players were yellow-carded by referee Romain Poite, despite clear grounds under World Rugby's crackdown on dangerous tackles to dismiss both players.
The reason given for downgrading the punishment on each occasion was that the opposition player was dipping when contact was made.
The Hodge verdict came barely 24 hours after World Rugby issued a powerful statement criticising the performance of officials at the World Cup.
A series of high-profile errors prompted the game's global governing body to concede that the officials' "performances over the opening weekend were not consistently of the standards set by World Rugby and themselves".
Wales assistant coach McBryde said: "Players are more than aware of the sanctions, and hopefully we won't see too many of them during the World Cup.
"It's a tough one. Anybody who has played rugby knows that things happen in a split-second.
"The aggressive nature and collision dominance that is spoken about in attack and defence means you have to be bang on the money.
"It's easier said than done when the fatigue has set in. If the conditions are humid and players are tired, that is when errors are made.
"Things happen very quickly in a game of rugby, and some calls are tough and others are not so hard to make.
"It's an ever-changing world in rugby with the influence the TMO (television match official) has. Players know they will have to do the utmost to keep their focus and concentration to not make silly errors."
Wales continued preparations on Thursday for the Wallabies encounter, with centre Hadleigh Parkes and hooker Ken Owens both taking part in training after suffering knocks during a 43-14 victory over Georgia three days ago.
Lock Bradley Davies – replacement for an injured Cory Hill – has arrived in Japan and was also involved in training.
Sunday's game is set to decide which team wins Pool D, with Wales hoping to back up a win against Australia 10 months ago by claiming another success, although before that result they suffered 13 successive defeats.at the Wallabies' hands.
McBryde added: "Everybody realises the magnitude of this game.
"We know we can beat them, but other than that, this is a completely different tournament, a different game with a lot more at stake.
"We will take heart from the fact we know we can beat them, but it is different circumstances. It's going to be a good battle."
McBryde also rejected any notion that Uruguay's shock Pool D victory over Fiji on Wednesday might have changed the group's dynamic.
"It does not change our mindset at all," he said.
"We are not looking further than the next game, and if we can beat Australia it puts us in a really healthy place.
"The Fiji game (against Wales on October 9) is going to be big, regardless of what has gone on.
"We know Fiji are a dangerous team on their day and will be hurting from that defeat, so if anything it will make them more dangerous."
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