The 25-year-old, who has made 43 appearances since leaving Sydney Roosters, has put pen-to-paper on a contract that keeps him at Langtree Park through to the 2015 season.

The New Zealand international insists he always intended to extend his stay, stating he has thoroughly enjoyed his time with the club.

"There was never any doubt that I would sign for the Saints," he told the club's official website.

"I have enjoyed my time at the club and I am looking forward to a successful season in our brand new stadium.

Challenging

"We have a lot of strength in depth at Saints and I'm sure we will be challenging on all fronts this year."

Saints chairman Eamonn McManus is delighted the future of one of the club's star players has been finalised.

"We are delighted to lock down Sia to a long-term deal," commented McManus.

"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."