"It might have been a change in guard in the organisation in the office of the King, I don't know. What I do know is Labour hasn't received a formal invitation and on the back of comments made at last year's Koroneihana it would be improper for Labour in an official capacity to assume they could just come."
Ardern was willing to attend on Monday for a church service and the King's speech, but Mahuta advised against it. She said Ardern was born in the area so was sensitive to the issues.
Morgan denied it was a snub. "What sort of nonsense is that?"
"Everyone is welcome there. There's no bias."
He said formal invites were not usually issued - political parties and other groups checked to find out when it was appropriate to attend and political leaders often went to Church Service and King's speech.
Asked if the possibility of a repeat of Tuheitia's speech might be a concern for Labour, Morgan laughed and said "s*** happens, we've all got to face our challenges, good or bad."
Tuheitia delivered that speech in front of Little last year, who said afterwards the King was abusing his office by endorsing Papa.
Little had said the Maori Party was not likely to be part of any government he led and after Ardern took over, Morgan had written to her to say the Maori Party was hopeful of a more positive relationship.
National leader Bill English was not attending this year either because he was campaigning on Sunday and Cabinet was meeting on Monday.
Treaty Minister Chris Finlayson and other Government MPs will go on Sunday as will Mana leader Hone Harawira, and The Opportunities Party Gareth Morgan. Maori Party MPs Te Ururoa Flavell and Marama Fox were going on with their iwi rather than as a party.
Mahuta was attending much of the anniversary commemorations as were Labour Maori MPs Peeni Henare - who is in line to take over his late father's seat on the King's council. Kelvin Davis was also attending on Monday.