The Sharks on Friday guaranteed Townsend a contract for the next two years, with an option for another two seasons.

The 28-year-old Townsend was set to enter the final year of his previous deal but was buoyed by the prospect of remaining at his junior club.

"I grew up here, this is where I want to play," Townsend said on Friday.

"I love playing for this jersey. It means a lot to me and I'm looking forward to the future. I'm very happy to be staying in the Shire."

The move continues the halves partnership between Townsend and Johnson, which steered the Sharks to an underwhelming elimination-final finish this year.

Cronulla coach John Morris, a teammate of Townsend in the Shire between 2011-13, described the No.7 as the most consistent player in the league.

"It's fantastic news. He's such an important part of our club," Morris said.

"No player in the NRL would be more consistent than Chad Townsend, on and off the field. He's the ultimate professional.

"He is a rare game manager, a player who can execute a game plan and he's a crucial part of our team."

Townsend's extension leaves veterans Josh Morris and Jayson Bukuya as the only regular first-graders without a deal beyond 2020.

There remains question marks about their backline, with the return of Jesse Ramien adding to a centre squeeze that includes Morris, Josh Dugan and young gun Bronson Xerri.

Australian Associated Press