Chris Fagan does not want to put limits on Brisbane's improvement but says playing finals in the next three years is a must.

The Lions coach signed a two-year contract extension on Tuesday night to tie him to the club until the end of 2021, a time period he says is long enough to make major inroads.

"That's the goal," Fagan said on Wednesday morning when asked about making finals.

"You want to try and get there.

"The focus for us has always been on improvement, and that might sound like a cop-out but it's a good thing to focus on because then you haven't got any limits on yourself.

"You can say you want to win 'x' number of games, but we might be capable of winning more than that. We might win less, who knows?

"Certainly we've got to be in the finals sometime in the next three years, that's without a doubt a goal of ours, it's got to be."

Since joining the Lions following the 2016 season, Fagan has overseen the improvement of a Brisbane team that is no longer the competition easy-beats.

Defensively Brisbane has improved by more than six goals in those two years and its percentage has risen by almost 30.

Young players have extended their contracts long-term, including high-end draft talent Hugh McCluggage, Jarrod Berry and Cam Rayner, rubber-stamping a cultural shift.

Although the wins haven't come yet, Fagan says he can see similarities with Alastair Clarkson's Hawthorn from the mid-2000s.

"Last year when I turned up I started studying rebuilds of footy clubs and what they looked like and how they progressed and I can see similarities to Hawthorn," Fagan said.

"I wasn't there when Clarko first turned up … he'd already been there three of four years (when Fagan arrived in 2008).

"When you look at wins and losses and percentage and those sorts of things they did to rebuild that club, we're doing similar things here.

"It's a good sign.

"I feel like a lot of the hard work has been done over the last couple of years and we can see the team's starting to get a little bit of belief and becoming way more competitive this year.

"I think we've created an environment … where our players are really happy to come here every day."