Looters are scaring Adelaide residents in the middle of the night on the site of a major upgrade of South Road.

Up to 120 houses are to be compulsorily acquired for the project and looters have been quick to move in on abandoned houses to claim valuable items.

But residents still living in the suburb of Croydon say looters are knocking on their windows at night to see if anyone is home.

One, named Jordan, said the situation was "nerve wracking".

"We had an incident a few weeks ago when the neighbours ended up calling the cops because we had people coming into houses down the street," she said.

"People are peeping through fences and things like that, knocking on windows and doors in the late hours of the night and early hours of the morning.

"As soon as they've noticed someone is home they run off."

North-South Corridor upgrade director Wayne Buckerfield said a security company was engaged several months ago to do regular patrols of the area.

He said the company had already "stepped up patrols" but would consider doing more.

Heritage items to be offered to renovators

Mr Buckerfield said the South Australian Government tried to recover items of "significant heritage value", such as old fireplaces and stone work, from acquired houses.

The items would be put in storage and made available for people renovating homes in the area.

"There's a bit of a race with looters at times on that issue," Mr Buckerfield said.

"In addition, there are other materials that have value, not heritage value, that are basically salvaged by the demolition company."

He said the Government received a better price for demolition works if the company could salvage valuable materials.

The current project includes upgrading a 3.7 kilometre section of road between Torrens Road and the River Torrens, with 1.4 kilometres of the new road to be dedicated to non-stop travel.