Four years ago in Qatar, Leckie scored a brilliant goal to help the Socceroos down Denmark 1-0 and put themselves into the Round of 16 for the second time in Australia's FIFA World Cup history.

Now 35, the winger-turned-midfielder is coming off an injury-plagued season with Melbourne City but is eyeing a fourth FIFA World Cup after being called into the Socceroos' training camp in Florida.

"It’s been a frustrating time .... but I guess I’ve just always had the mentality that I could get back," Leckie said.

"Without injury when I’m out there, I’m still capable to be in good shape.

"I don’t feel like I’m slowing down in any way, and the key has been to try to stay fit. I’ve still got a lot to give when I’m fit."

Leckie struggled to get back on the pitch for Melbourne City after hip surgery in December but impressed on his return in April.

Popovic all but confirmed Leckie would be part of his squad if fit, and singled him out for praise after he played 120 minutes in City's shootout loss to Auckland FC in the A-League play-offs.

"It will come down to his body, but if you just look at the quality he could (produce) at 35 with no football under his belt, a young player can’t do that," Popovic said earlier in May.

Leckie said he was glad of the compliment and was working hard to reward Popovic's faith.

"I’ve really put my head down in this camp and tried to work hard and do everything right to give myself a chance," he said.

"I’ll put my hand up to help any way the boss thinks I can."

Australia kicks off its 2026 FIFA World Cup finals campain against Turkey in Vancouver on 14 June (AEST) and also plays co-host United States and Paraguay.