A man is in a serious condition after being attacked with a hammer by three armed men wearing balaclavas during a home invasion in Melbourne's south-east.

Police said the offenders broke into a home on Henderson Road, Keysborough, just after 2:00am.

The man who was attacked by the group was taken to hospital with serious, but not life-threatening, injuries.

The other occupants of the house — three adults and a baby — were unharmed.

The offenders fled without taking anything, according to police, who believe it was a targeted attack linked to a similar incident last year.

The three men fled in vehicle that was waiting in front of the house, and was driven by a fourth person, police said.

Detective Senior Constable Tony Lavars said the men demanded cash but left empty-handed.

Police believe the attack may be linked to a similar incident last year. ( ABC News: Danielle Bonica )

"[The family was] in absolute shock, as you can imagine. There would be nothing more terrifying," he said.

Neighbour Nishadi said she woke up to the sound of someone screaming.

"I sat in bed and listened for about a minute or so, and then I heard the screaming getting louder, and then someone was banging on our door," she said.

"I woke up my parents and then I ran down, and my brother was already up … and he was already at the door speaking to her through the glass because we didn't know who it was."

By this stage they realised it was one of the women from next door asking for help.

Nishadi said while she was on the phone to emergency services her brother went over to give the injured man first aid.

She said the bedroom door appeared to have been bashed down with an axe.