Ahipene-Mercer's work on environmental issues often brought him into regular contact with the Wellington City Council. He was elected to the Wellington City Council in a by-election in 2000, taking the Eastern Ward position previously held by Sue Kedgley, who was elected to parliament as a Green MP. He was elected again in 2001 and 2004. "Mana News Service" reported that in 2001 he was one of only 20 Maori, out of a total of over a thousand New Zealanders, to win office in local elections that October. He is only the second Maori to be elected to the Wellington City Council and the first Maori to be elected since 1962.