In a terrific effort, more than 70 or the original 240 students - older and debatably wiser - gathered at Hunter Gateway Conference Centre on Saturday night.

"The guys did a terrific job locating so many old students from all over the place," former school captain Bruce Tyrrell said.

"We finished late, some time after 2am, but it was great to catch up again."

The dinner was to celebrate 50 years since the then youngsters finished school.

The effort to track down so many students fell to four people - Alek Schulha, Trevor Kedwell, Lloyd James and Barry Payton.

"In the old days you could do it easily with an electoral role," Mr Schulha said.

"At one stage we even had a policeman who could help, but he's retired these days."

So it meant a lot of phone calls.

"We'd find someone who would still be in contact with maybe one or two others, and it spread from there," Mr Schulha said.

"All up it took about five months to organise. We'd meet every Monday night.

"It was hard work but worth it in the end.

"And the venue was ideal - no stairs. At our age, believe me, you don't want stairs."

The Old Boys also raised $500 on the night that they will donate to national youth mental health group Headspace.