The 32-year-old, who played his 29th test for New Zealand against Scotland in late 2012, will join Wallaby winger James O'Connor and former rugby league international Karmichael Hunt in trying to turn around the struggling outfit.
The powerful former Otago Highlanders standout, who can play across the back row, has spent the last two seasons in Japan with Canon Eagles and will join the Reds at the conclusion of the Top League campaign.
"It was evident Adam is still genuinely craving the competitive nature of Super Rugby," Reds coach Richard Graham said in a news release.
"Whilst Adam will have a role as mentor to some of the younger players, his priority is to be the best player he can."
Graham oversaw a miserable 2014 season at the Reds in which the 2011 Super Rugby champions lost 11 of their 16 matches to finish third bottom of the standings.
