It will start off jackpot style, with Lotto presenter Russell Harrison handling the draw that will decide the performance schedule after the powhiri.
But coming back to the national stage is still a way away for Te Arawa, Mr Grant said.
"We haven't committed to going back into the festival and the reason for that is we want to see some improvement. At the moment things are in bad shape."
That includes the festival running at a loss. Mr Grant wouldn't say exactly by how much except that the figure would be "a couple of hundred thousand plus some."
Te Matatini's sideshow events detracted from what should be a prestigious event, Mr Grant said.
"The choice of watching the group on stage or watching something else - that should never be put before people. It should always be about kapa haka."
National Te Matatini chairman Tama Huata said it was positive that Te Arawa had returned to the national committee. But if they were there participating and making decisions, they should be performing.
"The question I have for Te Arawa is, 'When are your regionals?"'
As for financial management being a reason the region should not take part, that justification did not hold up to close inspection, Mr Huata said.
"They were in the arenas [in the past] when the festival didn't run according to plan in terms of some of the financial outcomes. I don't see it as being a really relevant point."
The 21s are invitation-only. Eight teams from the iwi's district will compete, and the other five will from Auckland, Waikato (2), the East Coast and Wellington.
Event details
* Each team taking part in the Te Arawa festival has only 21 members instead of the usual 40.
* Performances will be at the Rotorua Energy Events Centre, Government Gardens.
* Tickets cost $15 for adults and $10 for children and senior citizens.
* Performances start at 9am. Proceeds from a charity gold coin collection will be give to the Rotorua Aroha Mai Cancer Support Group.
