The powerful loose forward, who can play flanker or number eight and signed from Doncaster Knights, scored a try on his first team debut in the EDF Energy Cup against Harlequins and on his home debut against Montauban in the European Challenge Cup.
Director of Rugby Mike Ruddock admitted he was pleased to agree a new deal with the 24-year-old as he continues to build his squad for next season.
"We are delighted to announce that Netani Talei has signed a two-year contract extension," said Ruddock.
"Netani has impressed this season and has shown his ability as a ball carrier and at making breaks against the opposition defensive line.
"His skills are of an international quality and we believe that over the next two years he will develop and fully achieve his potential to become a world class back row forward.
"He has suffered a number of injuries that have halted his progression but hopefully when he is back we will see him put a run of games together in which he can show the skill that he undoubtedly has and that have attracted a number of other clubs. We are pleased he has agreed to remain a Warrior."