A man in his 20s is in a critical condition after a stabbing in Melbourne's south in the early hours of Friday morning.

Police were called to an address on Raleigh Street, Windsor, shortly after 2am after reports of two men fighting.

A Victoria Police spokesman said the men had left the scene by the time police arrived.

"A man in his 20s presented to a nearby hospital with stab wounds," he said.

Police have cordoned off Raleigh Street while they conduct their investigation. Credit:Patrick Herve

"We believe the men are known to each other and have closed Raleigh Street."

The investigation is ongoing.