The technology also helped claimants access £210,000
Lie detector software has saved a south London council almost £500,000 it was losing through benefit fraud.
During a phone call Voice Risk Analysis (VRA) software analyses minute changes in the voices of those claiming benefits to see if they are lying.
Lambeth Council said the use of VRA had proved so successful, it planned to extend the five-month pilot.
During the pilot, almost 1,700 people were assessed, of which 377 had their benefits stopped or decreased.
"Lambeth has a clear and tough policy of zero-tolerance of fraud," said David Ashmore from Lambeth's Revenues and Benefits department.
"We have a strong and multi-facetted counter fraud strategy. This cutting edge technology is another weapon in our armoury."
A further 261 people who were not aware of their full entitlement benefits, were given an extra £210,000.
"Under-claiming is quite common, especially as people's circumstances change," said Mr Ashmore.
"We use the system to quickly help those who are entitled to more.
"When their details have been verified, we can get assistance to them, often within a matter of days."