A school teacher from Wellington has been hailed as the woman who stopped convicted rapist Mike Tyson visiting New Zealand.

Juliana Venning complained to the Life Education Trust after discovering a letter in support of the former boxer had been sent on behalf of the charity.

The letter had been a significant factor in Immigration New Zealand approving Tyson's visa application.

Ms Venning alerted the trust's chief executive, John O'Connell, who said it was written without permission by a volunteer. The Herald can reveal the volunteer is retired Auckland businessman Peter High, 63, who said he was trying to help with fundraising for his local branch.

Yesterday, Tyson's visa was revoked by Associate Immigration Minister Kate Wilkinson despite the US celebrity declaring this week that he was coming to New Zealand "and there's nothing they can do about it".

Speaking about the Government turnaround, Ms Venning told the Herald: "I feel justified on behalf of every single woman who has ever been sexually assaulted, raped or abused or has been frightened by her male partner. I just hope that we can find much better role models who are really worth respecting, to follow.

"Here we have a person who has had a career path of disaster who is a sad and sorry individual ... who is wanting to come into our country pretty much under false pretences."

Ms Venning, who has been on the National Council of Women and stood for the Christchurch City Council in 2010, is also a freelance writer and counts children's book authors Joy Cowley and the late Margaret Mahy among her friends.

The Labour Party's spokeswoman on women's affairs, Sue Moroney, said of the teacher's actions: "The Government could learn a lot from what Juliana has done to stand up for the women of New Zealand."

In the volunteer's letter, obtained by the Herald, Mr High said: "Our charity will be the recipient of funds generated through Mr Tyson's activities in Auckland and New Zealand. It is estimated that Mr Tyson's activities will generate approximately $60K NZD. Although this Trust is run and maintained by a small group of volunteers we are in much need of funds ... for resources and operating costs. If Mr Tyson was not able [to] undertake his charitable activities in New Zealand and our organisation did not receive the funds generated by the event our organisation would be greatly affected."

Mr High has been a volunteer for about six years and wrote the letter on behalf of the Eden Roskill branch. He did not respond to messages yesterday.

Tyson was due to arrive on November 15 for his one-man show at Auckland's Vector Arena. He had been granted a visa despite serving three years of a six-year sentence for raping an 18-year-old woman in 1992.

Ms Wilkinson gave his application special dispensation.

Speaking from Las Vegas on Tuesday, Tyson said: "Fortunately, I am coming to New Zealand and there's nothing they can do about it and I'm so sorry, I'm sorry they feel disappointed and I'm just living my life."

Mr O'Connell said the trust was taking the matter "very seriously". He was clear that Mr High had acted with "the best of intentions".

Tyson's promoter, Max Markson, did not accept the revocation of the visa and said he would try to get a new one issued.