Carter will replace utility back Stephen Perofeta who fractured a bone in his foot during training which will rule him out for most of the competition.
Carter, who lives with his wife and three children close to the Blues base in Auckland, is a free agent after finishing with his Japanese club Kobe after their season was cut short due to the Covid-19 Pandemic.
“Two things from the lockdown that I realised was that I really enjoyed spending more time with my family and that I miss rugby,” Carter said.
“Leon is a good mate and we spoke about me helping out. For me it is a chance to mentor some young players and give back to New Zealand rugby.
“I have not played for several months so it will be a number of weeks before I am ready to be considered to play. And then only if my form warrants it.
“It’s an exciting opportunity to train in the same city that my kids go to school and my family are currently living. It will also be nice to share my experience with some of the young talent they have here at the Blues.
Blues Head Coach Leon MacDonald said he had kept in touch with Carter since his return from Japan and was keen to have him involved with the club.
“We have two designated 10s in Beauden and Otere, and Dan will be there to help them and our other young bucks. If he gets back into playing form that warrants selection, then he could help us as a utility back in the midfield or fullback.
“For Dan it is not about the money. He is here as a favour, with a desire to give back to the sport. We are only a few minutes from his home so it works out perfectly for everyone and we are thrilled.”