In a statement this morning, Cull said he was saddened to learn that Potiki had died.
"During my time as Mayor, I interacted with Tahu on various levels - he was a representative of Ōtākou Runanga, a cultural adviser to Council, and more recently acting chief executive of Aukaha consultancy.
Cull said he would often call on Potiki's wealth of knowledge and experience.
"We developed a great working relationship as well as an enormous amount of personal respect for one another over the years," he said.
"I particularly admired Tahu's staunch yet mellow persona. You were never left in any doubt as to his values and his resolve, but he had a calm and collaborative way of working with all people."
Cull said he extended his deepest sympathies to Potiki's whānau, friends and colleagues.
Comments on the Facebook post reveal an outpouring of grief for Potiki and best wishes for his family.