He's obviously hoping for a Penrith three-peat but Panthers great Greg Alexander is tipping the tightest NRL season in years.

Quietly confident Penrith will overcome the loss of several influential players and challenge for a third straight title, Alexander believes another six sides can also genuinely dream of premiership glory in 2023.

"There's half a dozen sides that are a threat," Alexander told AAP ahead of Thursday night's season opener between Parramatta and Melbourne at Commbank Stadium.

"The Storm will have another good year, I'm sure.

"South Sydney look very good, the Roosters with Brandon Smith joining them.

"The Cowboys went within a whisker of making the grand final last year. Parramatta.

"The Sharks will be good, too. They were very impressive throughout the trials.

"So there's half a dozen sides that will be jostling for the top four and there's probably going to be threats throughout the season from sides that won't make the eight."

As well as the fierce battle for the title, Alexander suspects a dozen sides will contend for the top-eight fight.

But you don't need to be a mathematician to work out that six won't go into one after locking in Penrith, Melbourne, South Sydney, the Roosters, Parramatta and Cronulla for finals berths.

"It's not an easy game because there's no doubt that the sides that finished near the bottom last year have improved," Alexander said.

"So I think it will be an even more congested season than it has been in previous years."

Despite losing, among others, NSW State of Origin hooker Api Koroisau to Wests Tigers, left-edge menace Viliame Kikau to Canterbury and winger Taylan May to a season-ending knee injury, Alexander is confident the Panthers retain the firepower and hunger to become the first team since Parramatta 40 years ago to win three successive premierships.

"You can't replace them because they're both pretty special players," the Penrith director and 1991 grand-final hero said of Koroisau and Kikau.

"But Mitch Kenny has played a lot at hooker and Soni Luke will come in and play the role of Mitch Kenny (from last year).

"Mentally backing up, that is the challenge.

"But the group of players that Penrith have are not a group of players who rest on their laurels.

"It's the individuals that make the team so special.

"So individually they're always trying to improve and I think that will drive them through the season.

"I'm excited for the year. It's going to be a great year of footy."