Earlier on Monday, Laidley accused Swans defenders of illegal tactics, including tunnelling, which involves targeting players' legs when they jump for the ball.
But Swans coach Roos said the criticism was only likely to motivate his side.
"As a coach I'm always mindful of what I say," Roos said.
"You can galvanise the other playing group. If our players read [Laidley's comments] they'd be very keen to get us there on Saturday night. And sometimes that one or two per cent can make a bit of a difference. And if the fans cheer louder, that'll be fantastic."
The tunnelling issue was raised after the Swans and Roos played out a draw at Telstra Dome in round six this year. Laidley singled out Craig Bolton and Leo Barry as two of the players responsible.
"Normally when we talk to the umpires, we keep that confidential. That's his (Laidley's) prerogative. I don't know if there's an agenda there, but given his comments, I thought it appropriate to speak to the umpires department," Roos said.
"I can't worry too much about what Dean says. But as for North Melbourne, I don't expect them to play as badly as they did (last) weekend. They're a very, very good side."
Roos said after speaking with the umpires department this morning, he's satisfied that there are no problems with his men.
"I don't even know what it is," he said of tunnelling.
"That's what I asked. You can't bump, push, block or hold. So it doesn't matter if a guy runs and gets pushed out of a contest; that's a free. If a guy jumps and gets pushed, that's a free.
"Some forwards are more athletic than others. Some jump when they go for a mark, and if you're bodying them up when they jump, it's a free. But you don't get a free for tunnelling as opposed to pushing. They're both pushing. So we need to be clear on what we're talking about.
"But given Dean's assessment, I just rang to clarify what the rule is. It's a strange term in a sense. So I've got clarification of what the rule is, and obviously earlier in the season there were a couple of incidents that were highlighted.
"We just expect the game to be umpired as it normally would. And I've no problems with the way my defenders go about playing their footy."
