Plans are under way to bring Dubbo High School's class of 1965 back together at a reunion on the first weekend in May.

Fifty years ago about 120 teenagers came together at the school to complete the Leaving Certificate before the introduction of a new qualification.

Reunion co-organiser and 1965 graduate Jill McCann said even though it was a large group they were close.

"Part of that was Dubbo High was the only full high school so all of our social and sporting lives revolved around it," she said.

In 1965, Dubbo South High had only just started with junior students and St John's College didn't exist, Mrs McCann said.

The Catholic schools were the De La Salle College for boys and the Convent for girls and both only went as far as the old Intermediate Certificate, she said.

Neither Narromine nor Gilgandra offered senior schooling.

"So Dubbo High was the only school where students could do the Leaving Certificate and many students saw this as their last opportunity," Mrs McCann said.

Her final year of high school involved vying with Orange High School for the Mulvey Cup trophy for debating.

"The Mulvey Cup was a big deal in the 60s and was broadcast live on local radio - it was held at night after the traditional welcome to the visiting Astley Cup team," she said.

"In 1965 we won the Mulvey Cup - my sister Libby Gleeson and Wally Howe and I were the members of the team.

"To launch Education Week that year, Prime Television did a televised debate between us and Bathurst High School."

Mrs McCann said about three-quarters of the class were boys which was "typical of the times".

"Lots of girls didn't go on - there were other job opportunities if you didn't," she said.

Grahame Marchant said he and his mates played football and cricket and soccer.

"Wednesday afternoon was sport day," he said.

Janet Rice came to Dubbo High in 1965 for her last year at high school after previously attending a small all-girls school in Queensland.

"I remember Astley Cup and being in the team, that was nice when I was new, it was a good way to make friends," she said.

"I played basketball - what's now called netball.

"We used to get thrashed by Orange High."

Mrs McCann said they were trying to contact all members of the class for the reunion, which was for both those who completed the Intermediate Certificate in 1963 and those who went on to complete the Leaving Certificate in 1965. She invited them to email dubbohigh65@gmail.com

The Leaving Certificate was replaced by the Higher School Certificate and secondary schooling expanded to six years.