The 27-year-old, who joined the Irish outfit from Auckland Blues in 2011, has claimed that he is "really enjoying" his time at the club.
"I am really enjoying my rugby here at Ulster so I am pleased to be staying for another three years," he told the club's official website.
"We have a fantastic squad of players and we play a great brand of rugby. It has been a successful season so far and hopefully we can finish the campaign off with some silverware."
Ulster finished top of the RaboDirect PRO12 table this season.