UNDER-ACHIEVING Fremantle shouldn't be underestimated.

That's the new consensus around the league and coach Mark Harvey has warned opposition clubs about taking his side lightly, with finals aspirants at most risk.

North Melbourne ruckman Hamish McIntosh, whose club heads to Perth to take on Fremantle this weekend, won't make the first mistake.

"They're a dangerous side," he said. "I know they've only had the one win but you've got to think of the games, they've been in front four or five games going into three-quarter-time against quality opposition. They only lost to Geelong by a point.

"They may only be 1-10, but they are a much better side than that. Going over there as well, playing them on their home ground is going to be a very tough challenge."

With strong support for the Kangaroos in the west, Subiaco Oval has generated three wins from the club's last four clashes with Fremantle at the venue.

And Fremantle has lost all five of its home games this year, with its sole victory coming in the away derby against West Coast.

"You take a bit from it but I think you can't take too much ... they've got a new coach there now [and] new young players coming through like (Rhys) Palmer and (Garrick) Ibbotson are giving them a bit more drive," McIntosh said.

"We've got a little bit of confidence going over, we've got a great supporter base over there in Perth – a lot of Kangaroo fans when we go there – and that's always great to have that support there.

"It's a big ground, it kind of suits our running players like Boomer (Brent Harvey) and Wellsy (Daniel Wells) and we'll just be looking to perform."

And with North Melbourne on the fringe of the top eight, every win from here is crucial.

"It's definitely a must-win for us," McIntosh said. "We're sitting eighth now with plenty of teams chasing our tail.

"We've got to get a win on the board."