Papalii said the decision to remain with the Raiders in Canberra is based on discussions with his family and friends.
“Over the past couple of weeks I’ve spent a lot of time talking with my family about this decision and I’m comfortable that it’s the best thing for me, my career and my family,” Papalii said.
“It’s been a really tough decision to make, but in the end I had to do what was right for my family and I know I’ve done that.
“The Raiders have given me the chance to start my NRL career and I’ve made a home in Canberra for myself and my family."
Raiders chief executive Don Furner said the club had agreed to terms with Papalii and said they were ready to move on and let Josh continue with his career.
“Josh is an important member of our club, he’s come through our junior development system and it’s important for us to retain as many of our talented juniors as we can,” Furner said.
“We’ve agreed to terms with him for a further three seasons and we’re excited about his future at this club."