Mall owner Forest City began testing the technology last week on ‘Black Friday’ and planned to run it until New Year’s Day to get a better understanding of shopping behaviour and movement patterns on its premises.

The technology, developed by Brighton-based Path Intelligence, uses a small number of monitoring units in any given location to recognise and track the signals given off by shoppers’ mobile phones.

Path Intelligence says the technology does not collect or access any personal information or phone numbers – information which is “proprietary and protected by the individual phone service provider”. Notification of the test was placed at the entrances of the malls, but Senator Schumer took issue with the fact that consumer could only opt-out of the test by switching off their mobile phones.

“Personal cell phones are just that – personal,” he wrote in a letter to Path Intelligence CEO Sharon Biggar. “If malls and retailers want to tap into your phone to see what your shopping patterns are, they can ask you to do so.”

Schumer asked Biggar to “immediately change the notice and consent framework” of the FootPath product so that consumer must opt-in to be tracked. He sent a copy of his letter to the Federal Trade Commission, which has recently pushed for consumers to be given more control over how they are tracked by companies when they are online.

A statement from Forest City, published by CNNMoney, said: “We have temporarily suspended further trial of the technology while we work with the system developer on possible enhancements, and in deference to concerns raised by Senator Schumer. We look forward to meeting with the senator and his staff, together with the system developer, to further explore his concerns.”