Investigators have also been able to access a person's Sky TV bills to establish if they are falsely claiming to be living alone.
New figures from the Department for Work and Pensions show almost 10,000 benefit cheats were convicted during the last financial year.
This compares to 7,040 convictions during the same period in 2009-2010 - the last full year of the Labour government - which is the equivalent of a 40 per cent rise.
During the same period more than 7,000 people received "administrative penalties" each year. Last financial year almost 16,000 were handed cautions compared to just 900 two years previously.
More than 166,000 cases were handled by the Fraud Investigation Service last year compared to almost 150,400 in 2009/2010.
Most cases are passed to customer compliance teams, to allow the service to "focus on higher risk fraud", officials say.
While the customer compliance team can cut benefits and recover overpayments, the FIS handles serious cases that end up in court.
Authorities spend almost £100 million every year investigating benefit fraud, with last year investigators recouping more than £215 million.
Iain Duncan Smith, Work and Pensions Secretary, admitted earlier this month that fraud and error was "rife" in the current welfare system.
Last night DWP officials said the sharp rise in court convictions was the result of a more aggressive drive to catch benefits fraudsters and investigators being handed more powers.
"Benefit cheats who try to steal from taxpayers need to know our investigators are actively targeting them," said Lord Freud, the Welfare reform minister.
"Our fraud investigators now have powers to check bank accounts, satellite TV bills, and credit reference records.
"Our teams are actively going through benefit claims to spotlight potential cheats and where fraud is suspected we have the power to film suspects and raid people's homes if need be."
He added: "Fraudulently claiming benefits is stealing from the taxpayer and taking support from others who need it.
"These cheats can end up with criminal records and will have to pay back their ill-gotten gains."
The department also highlighted the latest person to be convicted of claiming benefits while working.
Michelle Taylor, 40, of Bloxwich, West Mids, was handed a 12 week suspended jail term after being convicted of claiming more than £21,000 in benefits because she said she was unable to walk without support or a wheelchair.
Walsall magistrates heard that she was filmed walking to the gym after an anonymous tip-off to investigators.