Two students at an exclusive Melbourne boys college have been expelled after being caught during an alleged drug deal at school.

Marcellin College principal Mark Murphy says a staff member caught one of the boys allegedly supplying another student with a methamphetamine tablet at the campus, in Bulleen, last Wednesday.

The year 11 and 12 students were hauled before Mr Murphy before police and their parents were notified.

In a statement, Mr Murphy said: "On Wednesday 13th February a senior student brought an illicit substance onto the campus with the intention of supplying it to another student.

"Consistent with the College's Student Management and Expectation guidelines the College interviewed both students and immediately informed Victoria Police and the boys' parents of this isolated incident.

"The College concluded its internal investigation yesterday and is now in a position to inform the wider community. We will continue to work collaboratively with the Victoria Police investigation.

"The College prides itself on being a safe place for students to learn and grow. Therefore when that safe environment is compromised the College must act decisively in support of all our boys."

"The College does not condone the distribution, possession and or use of illicit and illegal substances and has acted to withdraw both young men's enrolment."

Police have confirmed they are investigating and say a 17 and 18-year-old boy have been questioned.

The school has refused to name the students involved.

The statement continued: "The College wishes to protect the privacy of each boy involved and maintain their dignity, while supporting their well-being in furthering their secondary schooling in another setting."