They have also accused the board of failing to take into account the impact it would have on parents and pupils using the programme.
The accusations were made in a formal letter which was sent to the board and the Ministry of Education on Wednesday.
The letter included a petition with 307 signatures, and impact statements from those affected by the decision.
"How an organisation does something is almost as important as what the organisation does," the letter said.
"We recognise that the board of trustees has a responsibility to make decisions in the best interests of the entire school community, considering the expectations of all stakeholders.
"However, the board also has an obligation to communicate with stakeholders in order to fulfil their role as our elected representatives.
"... we contend that the failure to engage with Georgies whanau fails to follow due process."
The letter argued that without consultation, it was not possible to fully appreciate the impact the decision would have on affected families.
Had the board followed due process, parents might have been able to come up with solutions that could keep the programme open, it said.
Some of the possible solutions were outlined in the letter.
"The board has an ethical duty to hear the impact of their decisions on the community they represent.
"It appears clear that, in this matter, the board has failed to value one group of stakeholder contributions, and appears disinterested in hearing parents’ views and suggestions on the matter.
"It is the hallmark of a decision made without regard to the cost to the whanau who use the service.
"Failure to consult with a significantly affected stakeholder group means that the group was denied voice, and therefore the decision-making process was flawed.
"We believe that the manner in which the board has undertaken this decision has caused harm to the relationship between the board and the school community, and to the reputation of George Street Normal School."
The letter asked the board to reconsider its decision to close the Georgies holiday programme and consider other options/models/changes to allow the programme to continue in a manner that met the needs of the whole school.
Former board member Tony Merriman, who served from 2007-18, agreed and also urged the present board to reconsider its decision and "honour the responsibility of holiday programme provision, assumed by the school in 2010".
A Ministry of Education spokeswoman said Georgies was an external programme run outside of school hours by the board of trustees.
"The ministry has no involvement in the programme, so wouldn’t investigate it."
Board chairwoman Greer Harper said she was unable to respond to questions yesterday.
