Caretaker coach Brett Ratten says North Melbourne will conduct a review of the chaotic final minute of its three-point defeat to Sydney, in which an interchange infringement cost it victory.

Swans tall Hayden McLean was awarded a free kick and 50-metre penalty for the Kangaroos' error and converted from point-blank range to seal his side's 14.9 (93) to 14.6 (90) win at Marvel Stadium on Saturday.

The critical moment came when Liam Shiels and Will Phillips left the ground and were replaced by Tom Powell and Hugh Greenwood, taking North Melbourne over the maximum 75 rotations allowed.

It was a dramatic end to former St Kilda and Carlton coach Ratten's first game in charge after he took the reins from Alastair Clarkson, who has stepped away from football indefinitely.

"We'll have a look at it during the week and work out how we can do some things better, but we're not going to worry about that," said Ratten.

"We had our chances. We'll have a look at it, review it and see if we can get better.

"There's sometimes a chat (in the coaches' box) about we're getting close with the rotations but there's nothing from a senior coach's point of view that I'm looking at the interchanges.

"There's so much going on in a game, so no, we just leave that to the bench."

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Sydney coach John Longmire said he had "no idea" what was happening when McLean put them back in front with the final goal of the game.

"We genuinely didn't know what the free kick and 50 was paid for," Longmire said.

"It wasn't until afterwards, someone told me after the siren had gone."