"We saw this as an opportunity for our students to showcase their talents . . . We did not consider that it could be seen as a political event. Performing is voluntary," he said.
On reflection Mr Buckland said he would review what he would do in future if a political party asked the school to take part in a variety concert.
"As with anything we do, it's our job to promote and enhance what's going on in our school. We've been transparent from the start but always more discussion is ideal."
Mr Buckland said he first met Dr Reti to discuss the concert on August 1.
The proposed concert was reported to the school board in his report for June 16 to August 4, and on September 9 the concert was mentioned in the school newsletter.
"We have an additional event this year where Bream Bay College has gone into partnership with our local MP Dr Shane Reti and the National Party to be part of the National Party End of Year Variety Concert," Mr Buckland said in the newsletter.
He said in hindsight "partnership" may not have been the best word to use.
Dr Reti said he approached the school about hiring the auditorium because he had visited it before and thought it would work well for the event.
"I'm aware Bream Bay College excels at performing arts and I thought this was also a great opportunity to showcase the students' talent and to help fundraise for a school group's overseas trip in 2017."
Mr Buckland said a school group would be using the intermission break as a fundraiser to head to Cairns to participate in Panzfest 2017.
Kim Shannon, head of sector enablement and support for the Ministry of Education, said supporting students to take part in a fundraiser for a political group is ultimately a judgment call for the school to make.