It is understood the year 13 pupils were sent home after senior teachers at the college used a breath-alcohol testing device to confirm the group had been drinking, last Friday morning.
Mount Aspiring College principal Wayne Bosley said the pupils were subsequently banned from attending the annual senior dinner - held later that evening.
No further disciplinary action had been taken against any of the pupils, he said.
"We felt the action taken was sufficient,"
He was pragmatic about the actions of the pupils and called for more support from parents.
"They could have had a breakfast together on the next morning [Saturday]. We are disappointed with the fact they had their festivities on the last day of term."
He did not want the actions of the 14 pupils to detract from the 110 other year 13 pupils.
College deputy principal Greg Thornton said two of the group were "visibly affected" by alcohol when they arrived for classes.
A "full investigation" was carried out which established how many pupils were involved, Mr Thornton said.
Mr Bosley dismissed a suggestion the actions of the group were stupid and brazen.
"It was a very silly thing to do. Sure, it was the last day of school and as 18-year-olds we have all been through this as well, They did a dumb thing," he said.
