Just as North Melbourne will struggle to have a truly closed training session, so has Mark Harvey failed to spy on them without being sprung.

Kangaroos coach Brad Scott had great fun on Friday teasing his rival AFL coach ahead of the Etihad Stadium match on Saturday against Harvey's Fremantle team.

Scott said near the end of Thursday's closed session at Arden St, one of his players pointed out that Harvey was watching.

The Arden St ground is open access, meaning it is impossible for North to stop rival clubs from engaging in espionage.

Spying on rivals' sessions has been a touchy topic at times in the league, but Scott laughed off Harvey's presence.

"I could have spoken to Mark Harvey yesterday at our closed training session, but he was in camouflage - he had the tree-coloured clothing on, hiding behind the goals," Scott said.

"It's fine, we can call it a closed training session at Arden St, but half of North Melbourne watch it.

"I don't know what he thinks he's going to get out of it, but it was just interesting."

Scott was more surprised that Harvey was watching them, rather than sending a forward scout.

"Too many coaches get too petty about that sort of stuff, I know our scouts have been kicked out of Fremantle Oval before," he said.

"I think it has absolutely no impact on the game.

"Maybe he was across at the Mazda dealership ... in the end he thought `well, Arden St is across the road, I might pop over and have a look'."

Scott was also in good humour about his twin brother Chris, who is an assistant coach at Fremantle.

There is speculation about Chris being a candidate for the Port Adelaide senior role.

Brad said he would have mixed feelings about his brother gaining the job, because Chris would be a tough adversary.

So it was suggested that Brad could solve that problem by employing Chris as a North assistant.

"He's been telling me what to do for 34 years, I don't think he'd cope with being told what to do," Chris said.

Harvey good-naturedly returned serve, saying he assumed the training session was open.

"I was in a khaki outfit. I was actually looking at a car and it wasn't a Mazda," Harvey said at Fremantle training in Melbourne.

"I just happened to look over and they were training so I just wandered across for 10 minutes to have a look and then wandered back.

"I thought it was an open session because there were a lot of people watching.

"I didn't break any ethics and there wasn't any malice in it - he [Scott] can come here and have a look now if he wants."

Harvey good-naturedly returned serve, saying he assumed the training session was open.

"I was in a khaki outfit. I was actually looking at a car and it wasn't a Mazda," Harvey said at Fremantle training in Melbourne.

"I just happened to look over and they were training so I just wandered across for 10 minutes to have a look and then wandered back.

"I thought it was an open session because there were a lot of people watching.

"I didn't break any ethics and there wasn't any malice in it - he [Scott] can come here and have a look now if he wants."

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