SIA Soliola has signed a three-year extension with the Saints.
The 25-year-old, who has made 43 appearances for the Club, has agreed a deal that will keep him at Langtree Park until the end of the 2015 season.
“We are delighted to lock down Sia to a long-term deal,” Saints Chairman Eamonn McManus said. “He has been one of our standout performers this season and at 25 years of age is still improving.
“He is a proven International and alongside some of the fantastic products from our famed Academy will form the hub of the side for many years to come.”
Sia added: “There was never any doubt that I would sign for the Saints. I have enjoyed my time at the Club and I am looking forward to a successful season in our brand new stadium.
“We have a lot of strength in depth at Saints and I’m sure we will be challenging on all fronts this year.”
The New Zealand international signed for the Saints after making more than 90 appearances for the Sydney Roosters, crossing the whitewash on 20-plus occasions.
He made his debut at the beginning of the 2010 season before ankle ligaments ruled him out for six weeks. His return against Warrington Wolves in the second row was a success but he ruptured his patella tendon in training and was expected to miss the entire campaign.
However, since then he has been an integral member of the squad, whose fearsome running and tackling style makes him one of the most exciting players in the game.