Slater missed Australia's 64-0 semi-final demolition of Fiji after aggravating a knee injury in the quarter-final against the USA.
Even the 30-year-old thought his Rugby League World Cup was over but his left knee has responded well to around-the-clock icing and the Melbourne Storm fullback is now considered better than a 50-50 chance of playing.
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If Slater does complete a miracle recovery he will force Greg Inglis back to the centres, with veteran Brent Tate the man likely to drop out of the starting side.
Meanwhile, the Kiwis are sweating on the availability of Sydney Roosters superstar Roger Tuivasa-Sheck after he suffered a lower-leg injury late in his side's dramatic 20-18 semi-final victory over England.
The 20-year-old, who scored a double at Wembley, will be monitored by medical staff early in the week before a decision on his availability is made.
Veteran back-rower Frank Pritchard is also under an injury cloud with a hamstring injury that kept him out of the semi-final.
But it is not all bad news on the injury front for the defending champions, with giant winger Manu Vatuvei certain to return after sitting out the England game with a groin injury.
Meanwhile, Kangaroos skipper Cameron Smith said his side's impressive performances in their past four games will count for nothing against the dangerous Kiwis in the Rugby League World Cup decider at Old Trafford.
The Kangaroos have not conceded a try in their past four outings and will enter the decider as favourites.
But Smith, one of five current squad members who played in the shock 34-20 Rugby League World Cup final defeat to the Kiwis in 2008, said recent form will count for nothing on Sunday.
"As we've learned in the past the results in the last four weeks don't matter at all, all that matters is how we perform next weekend," he told NRL.com.
"It was great to get the win (against Fiji) but we all know what's ahead of us, we're playing against the Kiwis who are a very good side and they got us the last time we played in a World Cup final.
"They had a really close (semi-final against England) and only just scraped home in the last 10 or 20 seconds but I know they'll be well prepared for next week.
"There's going to be a lot of questions about who's had the better preparation – we sort of started with a harder match and they finished with a harder match.
"But we're not too concerned with how they're travelling or whether they're building or what's happening in their camp, we're worrying about ourselves and I think we've improved each week."