Senior Maori MPs are explaining why politics and protest is part and parcel of Waitangi Day.

This year's events are expected to draw some marches, with tensions within iwi over the Government's signing of the TPP which may affect the Prime Minister's ability to attend.

Labour MP for Te Tai Tokerau Kelvin Davis said the signing of the Treaty was a political event and it's a day of the year where people can have their voices heard.

He said 364 days of the year they're ignored.

"This is the day that people come out and express how they feel, and the National government and previous Labour governments have copped it in the neck and that's the way it is and we just need to expect it."

Mr Davis said the Prime Minister has a right to speak at Te Tii, but should expect a robust reception.

Security permitting John Key will be attending events at Waitangi this week, there had been some division amongst Ngapuhi as to whether he should be invited on to the lower marae and whether he should be allowed speaking rights.

Mr Davis said if you welcome someone onto a marae they're entitled to speak, and it'd be a brave person who jumped up and tried to stop them.

"I'd say the Prime Minister should just go in there, if he is going to be welcomed on he should jump up, you know there'll be a reaction either way and I guess he has to prepare himself for all circumstances."

Green Party Co-leader Metiria Turei said doesn't know what specific protests are being planned for Waitangi, though she's aware of an anti-TPP hikoi.

"There will no doubt be protests at Waitangi that is part of the process, New Zealanders are entitled to protest that's perfectly lawful and quite right for people to have their say and their opinions."

She said the Government has an obligation to explain its actions at Waitangi during Waitangi Day commemorations.

This year's event has been tinged with controversy with Ngapuhi elders divided over whether the prime Minister should be invited onto Te Tii marae.

Ms Turei said the debate shouldn't be about the Prime Minister, nor should Mr Key make it about himself.

She argues it's about the role the Government plays in honouring the Treaty, the steps it's taking to improve the constitutional situation as well as the daily lives of Maori iwi around the country.

"Governments that can't deal with that are really problematic, this is the time for them to front up."