"I've never been to Brunei and I don't know much about it. I have heard that it is all jungles and beaches - and the kids are looking forward to seeing the monkeys.
"I will miss my job, though. I do really like working at Whanganui Girls College."
Brunei, which has 400,000 inhabitants, is an independent nation in the northwest of the island of Sarawak, the rest of which is divided between Malaysia and Indonesia.
"I'm excited but I also don't want to think about it yet, because I have so much to do before I leave," Mr Mokha said.
College principal Tania King said the position of a fixed-term assistant principal for the school had already been advertised.
"We're very reluctant to let him go," she said.