The 31-year-old had one season with the Men of Gwent and made 20 appearances for them during last season.
Newport Gwent Dragons chief executive Gareth Davies commented: “I would like to thank Netani for his contribution to the Dragons over the past 12 months.
“He is a dedicated rugby player and has been a great addition to the squad over the past season.
“We wish him all the best with his recovery and his future in rugby.”
