Renowned for his explosive running and fierce scrumming, Lutui, who joined Warriors in September 2006, has become a cult figure at Sixways.
The 29-year-old was recently named in the Tonga squad for the 2007 Rugby World Cup in France and has captained his country on several occasions in the past.
"We are very pleased that Aleki has decided to extend his stay at Warriors and that we can reveal a new two-year contract with him," said Director of Rugby Mike Ruddock.
"Aleki has built up a very strong reputation for himself in the Guinness Premiership and on the back on his excellent performances in the Rugby World Cup his reputation continues to grow.
"He is a tough tackling, all-action hooker who plays with a huge amount of aggression. However, off the field he is one of the nicest guys you could ever wish to meet and very popular with his team-mates and all the coaching staff."
Aleki revealed his decision to remain at Warriors for the next two years had been a simple one to make.
"It was an easy decision for me, I enjoy my rugby here at Warriors and would not want to play for another club," he said.
"The last 18 months have been fantastic with many happy memories for me. The way the coaching team wish to play rugby in the coming years excites me and I believe we are building towards a very successful future.
"I have many good friends at Warriors and my family is settled in the area and love Worcester. I also have a great relationship with the passionate supporters and look forward to not only playing for them in the coming years but also bringing them success."