Many criminals use identity fraud to make money
About 140,000 death records have been released since September by the General Register Office in a bid to prevent identity fraud.
The data has been accessed by pension funds, banks and mortgage companies.
Mortality checks found one woman claiming her aunt's pension to pay a mortgage 10 years after the aunt had died at the age of 98.
Home Office Minister Meg Hillier said the checks "will have a dramatic impact on fraudsters abusing people's deaths".
Estimates suggest that one in 400 pensions is still paid out after the death of the policyholder.
The Home Office said that four credit reference firms have now been accredited for the record release scheme and will be receiving about 12,000 records each week.
They can check the data against loan and credit card applications, insurance payouts and pensions to guard against fraud.
Keith Hollender, commercial director of the National Association of Pension Funds, said: "For many years, scheme managers have struggled to find an effective way to make sure they receive prompt notification of a member's death.
"Genuine mistakes, for example when relatives forget to tell the scheme that a member has died, and deliberate fraud, can cost pension schemes and insurers millions of pounds both in terms of monthly cash outlays and incorrect valuations of liabilities."