MacLeod, who coached Southland in 2020-21, will be responsible for the side's defence strategy. He has also coached the Blues A and Highlanders' Bravehearts teams.
Manu made his Super Rugby debut for the Blues in 2011 before transferring to the Chiefs in 2013, where he played 49 games before returning to the Blues in 2017.
After his Sunwolves stint, he ended his career having 91 Super Rugby caps. He will be Moana Pasifika's scrum coach.
Moana Pasifika rugby director Kevin Senio said the pair gave experience to the coaching group.
"Dale knows how to work hard and well in a challenging environment. He knows how to roll with the punches that Covid tends to throw at a rugby team, and he knows how to make the best of whatever hand he gets dealt.
"His work with Southland on defence got everyone's attention and his leadership style is a great fit for Moana," he said.
Senio said Manu was a talented player who gained a Rugby World Cup medal in 2015 when called up as an injury backup player for the All Blacks at the 2015 tournament.
"He has been coaching with Counties Manukau, and we know that he will bring a fresh player's perspective to his coaching. There's no one better to coach a scrum that someone who knows what it's like from inside the pack, and what's needed," he said.
Both men are working with the side at their home base at Mt Smart Stadium in Auckland.