The Green Machine have a top-four clash against the Sydney Roosters on Sunday, with both teams eyeing off a top-two finish and semi-final home advantage.

Canberra are hoping to break the 20,000 mark, which would be the biggest home crowd since their finals win over Penrith in front of 21,498 three years ago.

Early sales indicate they're on track for about 18,000-20,000 to rock up to what's being labelled as the game of the NRL season so far.

The Raiders are on a four-game winning streak, while the Roosters have won three straight.

Whoever wins will give themself the best chance of finishing second behind the Melbourne Storm at the end of the home-and-away season - ensuring they get home finals in the first two weeks of the post-season.

Raiders veteran Sia Soliola said it's one of their biggest home games since that electric 2016 campaign.

MORE RAIDERS NEWS

"Yeah I suppose so. Sunday football's really catered for the Canberra community," Soliola said.

"I know a lot of people are really looking forward to watching the game, just because 2pm on a Sunday afternoon at GIO is great.

"And given where we're at and where the Roosters are at in our positions on the ladder it just caters to a good game."

Raiders prop Josh Papalii was excited about the prospect of a bumper crowd and said that would spur them on.

"It's going to be a tough one. The boys are excited and I definitely know with the Viking clap the louder it is the boys seem to respond to that," he said.

Soliola was the Raiders' nomination for the Ken Stephen Medal on Monday - an award for NRL players' community work.

The 33-year-old volunteers at a soup kitchen, sleeps in the freezing cold to raise money for the homeless and cuts his afro for charity - just some of the many things he does to help others.

Soliola said he just tried to put himself in other people's shoes and act accordingly.

He was "really grateful and thankful" to be part of the group nominated, which also included Roosters fullback James Tedesco and Melbourne Storm winger Josh Addo-Carr.

"Seeing people happy, that's the main thing. That's a nice award for me," Soliola said.

"This game's provided me with a lot of good things, a lot of joy - whether it be emotionally, financially and every other way - but what good is it if you're not sharing that joy as well.

"It's all about giving back in those aspects for the love of the community."

NRL ROUND 21

Sunday: Canberra Raiders v Sydney Roosters at Canberra Stadium, 2pm. Tickets available from Ticketek.