She felt Whangarei District Council (WDC) had breached its own policies about disabled people's needs in the community, and complained to mayor Sheryl Mai.
Ms Mai replied immediately, saying she would ''look into how this happened and what will be done to ensure no one encounters this problem in the future".
She said disability-access to the stage was usually provided when asked for in advance, but the Stage Challenge organisers had not requested it.
Unlike the Capitaine Bougainville Theatre next door, which has permanently fixed wheelchair access, the stage in the larger auditorium is erected only when requested.
In future, organisations booking the facilities and requesting the stage be erected would automatically be asked if they required disability access, Ms Mai said.
The Auckland-based Stage Challenge organisers have not replied to requests for comment about the matter which saw students from different Northland schools unable to access the stage.
When he arrived at last month's event, a very disappointed Max feared he would not be able to be part of his school's performance - until the Boys' High students came to the rescue.
"They also had a participant who uses a power chair and, despite their drama teacher having informed the organisers that this was the case, they encountered the same problem we did," Ms Thompson said.
During the afternoon, the WBHS students regularly checked on Max to make sure they were there at the right time to help him onto and off the stage, she said.
"Eight of their finest lifted his chair onto the stage so Max could perform alongside his peers and experience the thrill of delighting a packed out theatre, with his family present, and we couldn't have been more proud."
Ms Thompson said the council's commitment to equity and access for people with impairment was clearly outlined in the its Growth Strategy - Sustainable Futures 30/50, Strategy Development, Implementation Plan and Long Term Plan documents.
She was surprised they had not been adhered to at a council-owned facility.
Jonny Wilkinson, chief executive of Northland disability advocacy group Tiaho Trust, said he believed the incident was isolated and due to a breakdown in communications.
"However, this case highlights the need for a greater awareness all round. A wider awareness can mitigate a lot of the issues around disability access," Mr Wilkinson said.
He said Max's experience was an all too common story.