The Wallabies haven't won the Bledisloe Cup since 2002 and they will be aiming to end that 16-year drought during the upcoming three-match series.
Beale has played 74 Tests since making his international debut in 2009.
But it has been the 29-year-old's form in recent years that has really caught the attention of Mealamu.
While fullback Israel Folau remains the Wallabies' biggest star, Mealamu believes it is Beale who holds the key to victory during the upcoming Bledisloe Cup series.
"I've seen him reinvent himself," Mealamu said of the speedy centre.
"Being a rugby player that played for a long time myself, you can appreciate that as he's getting older, he's getting better, which is great.
"He's one that we'll have to keep an eye on. He just looks comfortable in his position, he looks confident. It looks like he's taking opportunities and backing himself."
The Wallabies will take part in a trial match on Friday in a bid to get them match-ready for the August 18 clash with NZ in Sydney.
Coach Michael Cheika initiated the trial after watching his team get trounced in last year's Bledisloe Cup opener.
"It's very clever from Cheika," Wallabies utility back Dane Haylett-Petty said.
"During the last two Bledisloe (series), we've had probably four weeks off between Super Rugby and the Bledisloe, and been blown away in the first 20 minutes.
"We probably weren't quite prepared enough. So I think this is a great initiative to bridge that gap a bit."
Mealamu said he noticed an increase in physicality from the Wallabies during their recent series loss to Ireland.
He expects the upcoming Bledisloe Cup series to be a hard-fought affair.
"The series for the Bledisloe usually come down to one game, and within that game it's just a couple of moments," Mealamu said.
"Even though we've been lucky to be able to keep that piece of silverware in our cabinet, it's always been really close."
With Samu Kerevi and Tevita Kuridrani injured, Cheika will consider switching Folau to outside centre.
Reece Hodge and Curtis Rona are other options for the No.13 jersey.