Sophisticated burglars have escaped with more than $4 million in jewellery and cash in a series of targeted attacks on homes in an upscale Melbourne suburb.

Up to 70 homes in the north-eastern area of Manningham were robbed last month, prompting Victoria Police to issue a plea for information from the public.

Investigators have urged residents to report any suspicious people, vehicles or activity.

In one case, $250,000 in cash and $3 million worth of jewellery were stolen from a house.

Detective Senior Sergeant Matt Volk said officers were providing a highly visible police presence in known “hotspots”.

“The majority of these burglaries have been occurring on Friday, Saturday and Sunday evenings between 6pm and 10pm,” he said.

“In many cases, alarms have been disabled or ripped off the walls completely.”

He also said the burglars were well-organised and often operated in groups of two or three.

Investigators released CCTV footage of one of the burglaries that occurred at a Donvale residence in April.

Two men can be seen entering a White Lodge Court property in the evening, wearing masks, black gloves and jackets with hoods.