The day started with a full powhiri (welcome) followed by the unveiling and a hangi.
Mrs McGuire said the day was also about the renewal of culture in local youth, who played a big part in the days festivities. "It's about the revival of kapa haka and waiata. Putting the gloss back on them."
Labour leader David Shearer flew in from Auckland to be part of the special occasion.
He said the Kohupatiki Marae was important to the party for many reasons, as it is also the marae of Meka Whaitiri's mother, the candidate Labour has put forward for the now unoccupied Ikaroa-Rawhiti seat.
Mr Shearer said the death of Mr Horomia had left a big gap in the party. "He was our matua, our advisor, our guiding light."
Mrs Whaitiri was also in attendance. She said it was important to her to acknowledge 100 years of the marae she grew up on. "It's also really important that we bought Parekura's kawe mate (memory) to the marae. It's great to see his family here."
Organisers are planning to be on the marae for the next three days.