She said the allegations, made by Maori Television's Native Affairs last year, were "unfounded at the moment" and she stood by all purchases she made using trust money.
The trust is in charge of about $80 million in funding to 496 kohanga reo - Maori language preschools. It is paid $2.56 million a year by the Ministry of Education.
Dame Iritana said she had deliberately kept quiet about the allegations because of the investigations, first an Ernst & Young report and now a Serious Fraud Office investigation into the trust's subsidiary Te Pataka Ohanga.
She said she welcomed the investigations and that her spending was analysed as part of an internal review. "It's not a problem to me."
She would not say why her daughter-in-law Ms Tawhiwhirangi was dismissed.
"We're not answering those questions at the moment. The time will come."
Trust member Tukuroirangi Morgan said the EY report had cleared board members of mismanagement and misspending of taxpayer money, though the consultancy was not commissioned to look at Te Pataka Ohanga.
Asked why Native Affairs was banned from the press conference Mr Morgan closed off the questioning and said it was the trust's right to decide which media representatives it would talk to.
He ordered reporters to stick to questions about the hui or the press conference would end.
The hui unanimously agreed that a working party would consult kohanga reo members over major operational changes and report back in eight months.
It also agreed to resist "Crown intrusion" after the Government effectively set a deadline of April 30 for the trust to get its plans in order or risk losing its role in dispensing the $80 million.
"The Minister [of Education Hekia Parata] has made some statements in relation to circumventing further funding," Mr Morgan said.
"It is the view of the Kohanga Reo movement that the intrusion by the Crown is unwelcome."
Asked if the trust would ignore the April 30 deadline, he said it would seek an audience with appropriate ministers of Parliament.
Kohanga Reo National Trust
• The troubled trust has been under fire since claims last year that its chairwoman Dame Iritana Tawhiwhirangi approved spending of taxpayer money by her daughter-in-law Lynda Tawhiwhirangi on personal items.
• Hui has been held with 1200 members from 496 kohanga reo to discuss the need for major operational and governance changes.
• The Government had given an April 30 deadline for changes but the hui was unanimous in saying more time was needed.
• A working party has been set up to consult with all kohanga reo over the next eight months.
