A father and daughter may have been dead for a week before they were found in their house in Melbourne.

AN elderly man and his daughter may have been dead in their Hoppers Crossing home for more than a week before being discovered.

Neighbours who had just returned from holidays alerted police late last night.

The man, in his 90s, and a woman in her 60s were found in their Minogue Cres unit by police, who said there was nothing suspicious about their deaths.

Detective Sgt Mark Hatt from the homicide squad said the pair had been dead for some time.

Neighbour Barry Beer said he had just returned from holidays and became suspicious when he noticed their mailbox had not been emptied.

"I climbed the back fence and ... I called the police," he said.

Mr Beer said both were in poor health and he believed the daughter might have passed away first and her invalid father would not have been able to live without her.

"She did everything for him," he said.

Cheryl Beer said the pair were referred to in the street as "the twins" because they did everything together.

"Now they have died together, too. It's very sad," she said.

She said it was not unusual not to see them for a week at a time.

Neighbour Kevin Hoy said he saw the pair walking once a day and that the daughter had doted on her elderly father.

"It's very sad news, everybody knew them," Mr Hoy said.

"She absolutely doted on him, really cared for him and she was always with him.

"He used to ride on a motorised wheelchair to the plaza across the road with a white fluffy dog."

Another neighbour, who asked not to be named, said the pair's Maltese dog had been taken to a shelter last night.

"I don't think they had much family but she looked after him," she said.

Sharp Street Convenience Store owner Maise Khatib said the pair had often passed his shop on their motorised scooters.

"Most of the customers around here are in their 40s and 50s, they all sort of know each other," he said.

"Some say he was unwell and didn't get up much and others said he had a heart condition in the family."

Another resident who lived in the same unit block as the deceased, Iqbal Mahmud, 31, spoke of his sadness.

"It's certainly very sad because he was my neighbour. But the saddest thing was that they were left there and nobody knew they died," he said.

"The police were waiting around the house for hours, they were unsure what they might find, and then they broke down the door to take them out."

Police will prepare a report for the coroner to determine how the pair died.