Mackenzie: Australia have shown they can win without Sam Kerr
Striker Kerr, Australia's captain and best player, has not played a single minute of the three games in the campaign so far because of the calf injury sustained in training on the eve of the tournament.
She suited up for the final opening-round fixture against Canada on Monday but was not required as the co-hosts ran rampant with a 4-0 victory over the Olympic champions in Melbourne.
"We always want Sam on the field and she's a world-class striker but we've shown now that we have the depth and we can play any combination up front that we can still score goals," Arnold told The Australian Associated Press at the team camp.
"If she plays, she plays, if she doesn't, she doesn't. But we have our plan."
The Matildas squad took part in a light training session at their camp near Brisbane on Thursday ahead of their departure on Saturday for Sydney, where they will face the Danes at Stadium Australia on Monday.
Kerr is not yet training with the rest of the squad but Arnold thought she was progressing well with her specialised workouts.
"She has her own individual plan that she's doing with the doctor and physio and getting her ready to join in with the team," Arnold added.
"What she had to do, she looked like she was quite comfortable doing it, and she was in high spirits (afterwards), so I assumed it all went well."
Denmark finished second in their group behind England with the same record as Australia - two wins and a loss - and Arnold said they were not opponents to take lightly.
"They're a quite possession-based team," she said.
"They like to play football, they like to keep the ball, quite technical. They've got Pernille Harder in there as well, who's quite good at finishing.
"I wouldn't say we want them to have the ball too much."
