Former Newcastle back Mayerhofler returns to Albany as video analyst for the union, while ex-Blues prop Dowd leaves Wasps to join as rugby development manager.
"Craig and Mark are exciting appointments for North Harbour Rugby as we focus more on developing community rugby," said Harbour chief executive Brett Hollister.
"The primary purpose of these two roles is to improve our player and coach development pathways.
"Both individuals have long and distinguished playing careers and will bring a wealth of knowledge and experience to the North Harbour province."
Dowd and Mayerholfer return home ahead of the 2008 Air New Zealand Cup campaign.