The "Leipana" bromance set the NRL alight last season as Jordan Rapana and Joey Leilua emerged as the excitement machines of the competition on the Green Machine's right edge.

They'll go head-to-head with the Roosters' left edge pairing of Latrell Mitchell and Daniel Tupou, as the visitors look to continue the resurgence that's seen them climb to fourth on the NRL ladder at Canberra Stadium on Sunday.

While Leipana were yet to reach the heights of last season, they've still scored more tries between them than they had at the same time last year.

Rapana has scored nine tries so far this season - the same as he'd amassed after round 11 in 2016 - while Leilua has seven so far in 2017 - four more compared with last year.

It also gives them the edge over Mitchell (seven) and Tupou (six) this campaign, although the centre-wing combo have scored five between them in the last fortnight.

Raiders attack coach Mick Crawley said teams were finding ways to nullify their explosive attack, but he was confident they weren't far off hitting their straps.

He said the right edge had improved from last year, with the main problem coming from team handling errors.

That was allowing teams to camp themselves in the Raiders' defensive 20-metres and leading to more defensive pressure.

Crawley pointed out the Parramatta Eels had 20 more play-the-balls than the Raiders in the red zone, but they were still able to overcome that deficit to win the game.

"Teams defend a little bit differently now on BJ [Leilua] and Rapa and Blake [Austin] and the things that we did well last year, team's are a lot better prepared this year," he said.

"It makes all those things a little bit harder and teams are finding ways to nullify those guys to a certain extent - getting off the line fast, or markers blitzing out at those guys.

"We're working out strategies that work a little bit better for those sorts of defence."

As Crawley mentioned, teams have had more time to develop ways to minimise the impact of players like Rapana and Leilua.

Several teams, including Newcastle, have kicked the ball into touch on the fifth tackle to starve Canberra's big outside backs of the ball.

They've also been targeting the Raiders' right defensively, with Parramatta, the Knights and Manly all scoring tries that side.

While Leipana have scored more tries at the same stage, they've also missed more tackles.

Rapana missed 23 last season and Leilua 22, compared with 22 and 27 respectively so far in 2017.

It's an area Roosters Mitchell and Tupou will look to exploit and one that Raiders legend Jason Croker said could also help cut down Leipana's effectiveness in attack.

"When you target them you take away their energy as well. They've just got to choose the right option in defence and it should be all sweet," Croker said.

"There were a couple of games where they took the wrong option, but that's football, you've just got to get on with it and try and work together a bit better."

Crawley said from a defensive point of view, what happens on the edge could be a result of mistakes in the middle.

He also pointed out that while the Raiders were yet to fire in attack, they were still the fourth highest scoring team in the NRL.

"It all mirrors in - because we don't control possession as well as we want to it means the other team has more ball and gets more shots at us," Crawley said.

"Edge defence has a lot to do with the middles as well - if the middles aren't doing their job right, the edges get put under a little bit more pressure.

"While we're working really hard to fix that up, we don't think it's any particular player or particular edge, we just think it's our team in general."

NRL ROUND 12

Sunday: Canberra Raiders v Sydney Roosters at Canberra Stadium, 4pm. Tickets available from Ticketek. The jerseys will be auctioned at allbids.com.au.

Raiders squad: 1. Jack Wighton, 2. Nick Cotric, 3. Jarrod Croker (c), 4. Joey Leilua, 5. Jordan Rapana, 6. Blake Austin, 7. Aidan Sezer, 8. Junior Paulo, 9. Josh Hodgson, 10. Shannon Boyd, 11. Joe Tapine, 12. Elliott Whitehead, 13. Sia Soliola. Interchange: 14. Adam Clydsdale, 15. Luke Bateman, 16. Clay Priest, 17. Dunamis Lui. Reserves: 18. Dave Taylor, 19. Scott Sorensen, 20. Brent Naden, 21. Lachlan Croker.

Roosters squad: 1. Michael Gordon, 2. Daniel Tupou, 3. Latrell Mitchell, 4. Mitchell Aubusson, 5. Joseph Manu, 6. Connor Watson, 7. Luke Keary, 8. Jared Waerea-Hargreaves, 9. Jake Friend (c), 10. Kane Evans, 11. Ryan Matterson, 12. Siosiua Taukeiaho, 13. Zane Tetevano. Interchange: 14. Isaac Liu, 15. Lindsay Collins, 16. Chris Smith, 17. Mitchell Cornish. Reserves: 18. Nat Butcher, 19. Victor Radley, 20. Eloni Vunakece, 21. Brock Gray.