Formed just eight weeks ago, the choir, named Wanganui Hits Sydney, represents the core of Wanganui High School's performing arts students and includes year 9 to year 13 students.
"Most of them were in the cast of Annie and they are used to singing together," said head of music Jeanette Jones.
The signature piece performed by the choir in Sydney was a medley of spiritual songs with an Australian composition added in.
"The composer of that song was on the adjudication panel at the competition and he was very impressed," said head of drama Colin Hedivan.
As well as the Opera House, the students performed on the waterfront at Darling Harbour and in the conservatory at the University of Sydney.
"We sang as part of a massed choir at the Sydney Town Hall and we had four days to learn the song - it was a fantastic experience and we got to make friends with people from the other groups," said Sophie.
In Sydney for seven days, the students had some time out to explore the sights and cultural leader Finn Brown said he enjoyed visiting Chinatown.
"We had a competition to see who could find the weirdest food. And we visited Taronga Zoo which was a great experience."
Mrs Jones and Mr Hedivan encouraged choir members to commit to the choir for the coming year and work towards entering New Zealand competitions.
"I know year 13 students will need to give precedence to your academic studies in the coming months but it will be good to keep the choir going," said Mrs Jones.
Finn, who is also bass player with high school group Contraband, said he will continue to pursue music and singing when he leaves school at the end of theyear.
Sophie is not so sure but said she has enjoyed participating in the choir so much that "anything is possible".
