Sources have confirmed to RNZ that the former Crusaders star will join the Blues for the Super Rugby Aotearoa competition, which kicks off on Saturday week.
The 38-year-old's signing is expected to be announced at a media session in Auckland at midday.
The Blues coach Leon MacDonald messaged the team on Wednesday to tell them Carter was joining the side as injury cover for Stephen Perofeta.
"His motive is to give back to NZ Rugby by sharing his experience/knowledge with us.
"Great opportunity to learn from one of the games' greats," Macdonald wrote.