Body found at Melbourne school treated as non suspicious

Police are treating the death of a man who was found inside a school in Melbourne's north as non-suspicious.

A staff member of Lyndale Secondary College in Dandenong North alerted police after making the grim discovery about 7am while opening the school gates.

The school day went ahead for the students, with part of the campus cornered off as a crime scene for most of the day.

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Detective Inspector Dean Thomas earlier told reporters the death was being treated as suspicious.

He couldn't confirm whether the man died at the school.

"It's too early to say, we are going to try and piece together the male's movements and determine where this has occurred," Detective Inspector Thomas said.

"Whether it's happened there or whether he has been brought to the scene… we don't know yet, it's too early to say."

Police believe the man was of African appearance and in his 20s but he is yet to be formally identified.

Anybody who saw suspicious activity in the area between 7.30pm on Friday and 7am today is urged to contact Crime Stoppers on 1800 333 000, or online.