Henry coached the provincial side from 1992-97 as well as Super Rugby's Auckland Blues from 1996-98. After a stint with Wales he returned to New Zealand and was appointed to the All Blacks role in 2004, stepping down after their World Cup triumph.
Auckland have struggled in recent years and Henry said he was here to help.
"It's easy to criticise from the outside but let's try and make a difference from the inside. I'll be mentoring the coaches ... and the players and hope to make a difference," he said.
Auckland are New Zealand's most successful provincial team, having won 16 titles since the national championship was introduced in 1976. Henry won four of those titles from 1993-96.
The team, however, have not won the title since 2007, during which time arch-rivals Canterbury have clinched nine of the 10 championships.
They also flirted with relegation from the top division for the first time last season, only surviving after Waikato lost in the final round of the regular season.
Former Samoa coach Ieremia, who was appointed last month, hoped to profit from Henry's experience.
"Graham obviously has a wealth of knowledge around the defence systems and trends of the game with a track record that speaks for itself," Ieremia said.
"Additionally, a key aspect of Graham's involvement is his role as a mentor not only to the coaches, but most importantly for the players."
(Reporting by Greg Stutchbury; Editing by Peter Rutherford)
