Australia are on the cusp of reaching the last 16 of the World Cup for only the second time in their history, matching the achievement of a "golden generation" who made the same stage in 2006.

And Australia coach Graham Arnold said on Tuesday that his team's exploits in the Qatar can "put football on the map" at home and unite the nation.

Victory over Euro 2020 semi-finalists Denmark on Wednesday (at 10pm Cambodian time) will guarantee a spot in the knockout rounds, while a draw could also be enough.

Arnold declared that in a sports-mad country where football traditionally comes behind cricket, both rugby codes and Australian rules, the Socceroos "unite the nation" like no other national team.

Arnold said that the 1-0 win over Tunisia that put Australia in pole position to join the already-through holders France from Group D in the knockout rounds had put smiles on faces.

But speaking on the eve of the Denmark showdown, Arnold cautioned: "Putting smiles on Australian faces once is not enough, let's do it some more times."

Arnold is also looking at the bigger picture and what a good run in Qatar will do for football's popularity in Australia.

He wants change, including more investment at youth level, to grow the game in the country and hopes this World Cup will inspire future generations in Australia to take up football.

"I've said many times – it's not about me, it's about the game in Australia," said Arnold.

"To leave a legacy is huge," added Arnold, 59, who was assistant coach to Guus Hiddink at the 2006 World Cup, where Australia boasted the likes of Harry Kewell, Mark Viduka and Tim Cahill.

Arnold said the current Socceroos squad – which have plenty of heart but no world stars – had been inspired by the 2006 run.

"This generation, they were 10 years of age watching these guys," Arnold said.

"When you sit down even now in the lunch room this generation is talking about emulating the 2006 squad and achieving the same goals they saw when they were 10 years old.

"So it's about putting the game on the map a bit more in Australia.

"But again, there's so much more work to do, it's crazy."