Roos expressed frustration at the amount of free kicks the Demons conceded in their thrilling five-point loss to North Melbourne last round, identifying that as the key reason for the result.

"We gave away too many free kicks at the end of the day. I think they kicked six goals from free kicks," Roos said at the MCG on Thursday following the annual Breast Cancer Network Australia Pink Lady Breakfast.

"When you're playing a high-quality team, you can't gift them goals and I think that was really what we felt in the end was the difference in the game. So we've got to cut out them."

The Demons' performance against the Kangaroos was a vast improvement on their poor showing against the depleted Bombers in round two - a match they lost by 13 points.

But Roos said his team didn't have a "big margin for error" when it came to effort and intensity and suggested they would struggle to beat the Magpies if they didn't replicate Sunday's showing in Tasmania.

It's been a topsy-turvy start to the season for Melbourne with a win over the Giants followed by the loss to the Bombers and then pushing last year's preliminary finalists right to the line.

The Melbourne coach stressed the importance of eradicating wild inconsistency from their form.

"We're a youngish team ... we definitely see the improvement but the competition has improved," Roos said.

"We've got to try and iron out that consistency, but inconsistency comes often with young players going in and out, they get tired at different times, they need breaks, they go out of form.

"Overall we just want to try and improve every single week, that's one of our goals."

Collingwood and their coach Nathan Buckley have come under scrutiny this week on the back of their poor start to 2016, which included a shock 29-point loss to St Kilda last week.

However, Roos downplayed the prospect of the Magpies being more fired up on Sunday as a result of media criticsm.

"From a coach's point of view, we all know we're one disastrous game away from getting criticised and we're one good game from getting praised," Roos said.

"So I don't think there's too many coaches that focus on that at all."

Sunday's match takes on extra significance for Roos, who not only coaches his 250th AFL match but also joins Robert Walls on 606 matches played/coached in equal ninth position on the all-time list.

"He was my first coach [at Fitzroy], so the connection there is nice," Roos said.

"I still remember him telling me I was playing my first game, so catching up to Wallsy and levelling him, who I respected and was lucky enough to play under as my first coach, is probably more significant [than the 250-game milestone]."

Unsurprisingly, Roos nominated coaching the Swans to their drought-breaking 2005 premiership as the highlight of his coaching career.

Roos expected Jeff Garlett (ankle) to be available for selection this week after sitting out the Kangaroos match and Angus Brayshaw was also a chance of returning to the senior line-up.

Highly rated Christian Petracca is still a few weeks away from a senior berth, despite some impressive VFL form, but Roos indicated Jayden Hunt could make his debut against the Pies.