Former Port Adelaide star Kane Cornes has described Brent Harvey as the "hardest opponent" he's ever played against.

Handed the role of tagging North's number 29 over the best part of 15 seasons, Cornes says the match-up gave him "nightmares".

"To give you an example, Dom Cassisi and myself, we had the run-with roles; coming up against the Kangaroos we'd almost flip a coin as to who got Boomer. We both didn't want him," Cornes told Fox Footy's AFL 360.

"He sensed blood when I was playing on him. He knew your weakness to a tee.

"He knew that I couldn't play as a defender, so he'd just take me forward and kick three or four in a matter of minutes.

"He's my hardest opponent that I've ever played on."

Cornes said Harvey continued to amaze with his ability to kick goals and win the ball, even after 21 seasons.

"To think that in 427 games, 300 of those he's probably been tagged in," he added.

"He's still kicked 30 goals for the year, as a 38-year-old, and averaging 21 disposals.

"(It's been a) unbelievable career and (he's) the best player I've ever played on."