The figure was revealed in a council report ahead of an audit and standards committee meeting next week.
New cases investigated in 2020/21 included 10 of obtaining property by deception, four of right to buy fraud and 134 of unlawful subletting.
Many of these are still ongoing but 55 were closed resulting in 16 properties being recovered. In other cases, properties were abandoned, the tenancies were handed back or there was not enough evidence.
Over the past year, three cases were successfully prosecuted with a total awarded cost of £4,549.66 and there are four more cases now in the process of prosecution.
Council officers said: “It is difficult to fully determine the number of fraudulent tenancy cases as often the tenants hand back their tenancy when they are aware of an investigation taking place.
“This means that lengthy and costly legal action is avoided and the houses are once more available to be used by the citizens of Sheffield who need them.
“The council will always take the appropriate legal action if fraud can be proven, even if the tenancy has been given up.”
They added: “Housing Fraud casework has been hampered during the lockdown restrictions as we have not been able to carry out visits (as in normal procedures).
“Legal action has also been delayed due to the service not being able to carry out interviews under caution.”
It is part of a wider report on fraud dealt with by the council over the past year.
According to the National Fraud Authority, public sector fraud costs taxpayers around £20.3 billion per year and research by Policy Exchange found fraud and error during Covid-19 will cost the government around £4.6 billion.
Council officers said: “[The council] has robust processes to try to prevent and detect fraud. These are available to all staff and have become embedded into council processes. This should reduce the amount of fraud and aid in its early detection.”
The report will be discussed at the committee meeting next Thursday from 5pm.