One man is dead and two others seriously injured after separate knife attacks in Melbourne this morning.

Police said a man died after he was found outside a block of flats in North Melbourne, while two men in their 20s were attacked by a group on a street in Noble Park.

Police said the victim of the North Melbourne stabbing died at the Royal Melbourne Hospital after being treated by paramedics at the scene.

The area around the flats was cordoned off all morning. ( Supplied )

Emergency crews were called to the entrance of the flats, on Courtney Street, about 4:45am.

Police said they have not yet worked out the circumstances of the stabbing and were doorknocking the area this morning.

Russell Mulry, who works nearby on Queensberry Street, said he was shocked to hear what had happened in an area he said was not usually violent.

Police said the circumstances of the stabbing were not clear. ( ABC News: James Oaten )

"You get the few odd people walking around the streets as you do in every suburb and town, but I haven't seen anything out of the ordinary," he said.

"I park my car here most days and stuff, but I don't think I'll be doing that now that I know that someone has been stabbed a few metres from where I park my car."

The man was found at the entrance to the flats. ( ABC News )

In Noble Park, two men in their 20s were stabbed after they were approached by a group of men.

"Investigators have been told the pair were walking in the vicinity of Corrigan Road and Green Street about 1:00am when they were approached by five to six men armed with a knife, who made demands for cash," a police statement said.

In Noble Park, two men were attacked by a group in the street. ( ABC News )

"The men refused and an altercation occurred, with both sustaining stab wounds.

"The group then fled the scene with an amount of cash."

Both of the men were found on the street and taken to hospital.

Ambulance Victoria said the men were now in a stable condition in the Alfred Hospital.