The pilot scheme is using software supplied by Capita. The VRA technology measures slight fluctuations in the human voice known as "micro-tremors", which can indicate attempts to deceive.
The pilot is sponsored by the Department for Work and Pensions (DWP), and is part of a national initiative to look at the effectiveness of the technology in cutting fraud.
Claimants contacting the Lambeth call centre will be told they are being interviewed using the technology, and will be asked a series of 19 questions to test their responses.
Benefits staff can then ask for further evidence to support any suspicious claims.
Councillor Jim Dickson, cabinet member for finance at Lambeth Council, said, "I am delighted that Lambeth is piloting this new technology to speed up the claims of honest claimants and cause sleepless nights to benefit swindlers."
VRA technology is already used by the insurance industry to help combat fraud.