A fight between two men at a birthday party spilled into the streets of Melbourne's outer southeastern suburbs, police said.

Detectives said the men, aged 23 and 54, from the same family, were involved in a fight involving about 20 people. Police said some people left the scene before officers arrived.

Emergency services were called to a home in Clyde North just after 9.30pm on Thursday. When they arrived, they found two men suffering from stab wounds and despite medical attention, both men died at the scene.

Officer Janet Stevenson told reporters the pair were celebrating at a party at the home.

"There was an argument and it escalated into a fight and spilled out into the street. So at some stage in that fight two men were stabbed," she said.

"This was a private birthday party that was supposed to be a celebration but unfortunately had tragic consequences."

Detectives are looking for someone they believe left the area before police arrived, Stevenson said.

"We really need to talk to those people so we can piece together what happened last night," she said.

Stevenson urged anyone with information to contact Crime Stoppers.

"It's in everyone's interest, especially for this family who is grieving after losing two members. We really need to resolve this as quickly as possible," she said.

Stevenson said it was unclear whether the incident involved a single offender or whether a single weapon was used.

As detectives tried to determine what had happened, a crime scene was established and expanded into the nearby model home car park a few meters away.

Numerous forensic police and homicide detectives arrived at the scene shortly before 9 a.m. Friday, and an officer on the scene said they were expected to be there for most of the day.

Two SES tents remain on the street, one of which is covered with what is believed to be a body.

Neighbors were told to stay indoors as the police pursuit continued Friday morning.

Neighbors were shocked to hear sirens blaring in the otherwise quiet street at around 9.30pm on Thursday. They say there was a party going on at the home involved and it may have gotten out of hand.

"It's very scary," said one neighbor who asked not to be named.

"We actually spent a long time watching the police arrive, but they told us to stay home for our own safety."