A man is fighting serious injuries in hospital after he was shot, stabbed and repeatedly hit with a hammer during a home invasion in Melbourne's north-west overnight.

Five hooded and masked offenders broke into a house on Trentham Drive in Gladstone Park just before 1.30am where a couple were sleeping inside, Armed Crime Squad Detective Inspector Adam Tilley said.

A 60-year-old man awoke to the disturbance and confronted the group near the kitchen.

It's alleged multiple offenders broke into a house on Trentham Drive in Gladstone Park just before 1.30am where a couple were sleeping inside.

The group, who were armed with a hammer, knives and a gun, allegedly placed the firearm in the man's mouth and made demands for cash.

Police said they also repeatedly asked for another male, who is known to police but does not live at the home.

When he was unable to comply with their demands, the 60-year-old was shot, repeatedly stabbed and struck with a hammer multiple times, Tilley said.

The ordeal lasted for five to 10 minutes, after which the group left the man on the floor and entered a bedroom where a 57-year-old woman was in bed.

The group allegedly threatened her with a gun before they fled the scene in a white vehicle.

Detectives from the forensics team examined the scene today.

She was not physically injured.

The man was rushed to the Royal Melbourne Hospital, where he is receiving treatment for serious but non-life-threatening injuries.

The man was shot in the arm and suffered "multiple strikes" to his upper body, lower body and head region, Tilley said.

Early indications suggest the couple were innocent victims and are not known to police, according to Tilley.

A large crime scene has been set up at the Gladstone Park home.

"To be woken by five offenders, let alone armed with firearms, knives and also a hammer, is extremely concerning to us and that's why we're really seeking the public's support," Tilley said.

"If anyone has information, please come forward to either contact their local police station or Crimestoppers."

Safety messaging has been conveyed to the man who was named by the offenders during the assault.

Armed Crime Squad Detective Inspector Adam Tilley urged the public to come forward with information.

Tilley said he has not been in contact with police at this stage.

"We have been making enquiries to identify his current location, we obviously have concerns for his safety.

"We'd obviously like to speak to him in person and convey our concerns to him."

The offenders remain on the run.

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