The Labour Party is planning to arrive en masse today with leader David Shearer arriving back in New Zealand early this morning after cutting his trip to the United States, and other members of the caucus hiring a plane from Wellington.
Prime Minister John Key is planning to pay his respects on Friday.
Mr Horomia's body will taken on to Hauiti Marae at 9.30am today by one of his tribes, Ngati Kahungunu, along with Maori Affairs Minister Pita Sharples and Te Puni Kokiri officials, King Tuheitia, and Tainui.
The official Maori Party delegation will arrive tomorrow.
Te Aitanga a Hauiti tribal spokesman Wayne Ngata said the scale of the event was not a worry for the hosts.
"This is Maori Management 101. When we have a tangihanga you don't know who's coming, you don't know how many, how long they're going to stay and you don't know who's paying for it," he joked.
"You just deal with it.
"If you look that way there's the sea and our boats are out there now, if you look that [way] there are our farms we've got 25-odd mutton hanging there now, beasts are being killed right now."
The effects of the event which will end on Saturday are rippling out through the district.
On the way into the coastal village from the Gisborne end there are temporary 30km speed signs in place to warn the logging trucks that rumble through to slow down.
Gisborne Isite spokesman Ryan Raggett said virtually all motel and hotel rooms had been booked because of the tangi. Surrounding marae on the east coast were also gearing up to accommodate people.
Dr Sharples has asked the Defence Force to help and it has sent a transportable kitchen and caterers to help.
