HM Revenue & Customs paid informants £397,950 in rewards for tip-offs on tax fraud in the year ending March 2021.
Analysis of the government department’s accounts by law firm RPC found HMRC’s hotline had received 28,000 reports of fraud as of June this year.
But despite the government's Covid-19 support schemes posing greater opportunities for fraud since April 2020, the department still spent around £75,000 less on tip-offs than in the previous year.
An HMRC spokesperson said: "There will be times when it is appropriate for us to make payments to individuals for providing us with information that helps us tackle avoidance and evasion.
"We make these at our own discretion, based on what is achieved as a direct result."
Adam Craggs, RPC’s partner and head of tax, regulatory and financial crime, suggested HMRC "is under pressure" from the government to increase the tax yield following the pandemic.
He added: “With increased public spending during the pandemic, recovering unpaid tax will be a high priority for the Treasury as it seeks to increase government revenue.”
But HMRC disputed this.
The government estimated in its annual report for 2020-21 that £5.2bn of the money it paid out as part of the government’s furlough scheme was issued to organised criminals, fraudsters or simply paid out in error.
Back in July, HMRC made its first arrest in connection to alleged fraud relating to the furlough scheme.
The 57-year-old West Midlands man was part of an investigation into a suspected £495,000 Coronavirus Job Retention Scheme fraud.
He was also part of a suspected multi-million pound tax fraud and alleged money laundering offences, part of a ring of eight other men who were arrested across the West Midlands.
Since then, two Londoners were arrested in September last year on suspicion of fraudulently claiming on the scheme to the tune of £70,000.
And in May this year, a man and a woman from West Yorkshire were arrested for a suspected £3.4m fraud of the scheme.