Grandma, grandson stabbed to death in Melbourne

A grandmother and her four-year-old grandson have been found stabbed to death at a Melbourne home.

Police also found the woman's 61-year-old husband bound and gagged on the living room floor when they got to the Albanvale home on Tuesday afternoon.

A 45-year-old Chinese woman, who was at the Varsity Court address when police arrived, has been arrested and is being questioned.

The Vietnamese grandparents were babysitting their grandson while his parents were at work, something they did every Tuesday.

The grandfather is recovering from minor injuries in the Royal Melbourne Hospital.

Detective Senior Sergeant Stuart Bailey said the Chinese woman had arrived at the couple's home earlier on Tuesday morning, and an "altercation" erupted after the grandmother got home about 5pm.

Police found the 60-year-old grandmother dead in the backyard, fatally stabbed.

Her grandson's body was found in a bedroom after his grandfather, who was tied up in the living room, asked how he was.

"The scene is quite horrific," Det Sen Sgt Bailey told reporters on Tuesday night.

He said the boy's parents, who live at Maidstone, were obviously inconsolable and devastated.

There are four grandchildren in total, but just one was at the Albanvale house at the time.

Neighbours spoke of hearing a dispute at the address before the bodies were found.

A woman, who wished to be known only as Nasma, said she had lived in the area for more than 16 years and was shocked when she heard a woman and child had been killed.

"It's scary," she told AAP.

"Something like that, it just doesn't make you feel safe."

Homicide detectives will remain at the scene overnight, while several witnesses are assisting police at a nearby station.

No charges have been laid.