Some £2bn was deposited into National Savings & Investment (NS&I) accounts during February, data from the Bank of England has revealed.
NS&I accounts are backed by the government treasury, whereas most UK bank accounts are only covered up to £85,000 under the Financial Services Compensation Scheme (FSCS).
February's inflow compares to net zero in January as the same amount came in as was withdrawn.
In December, £700mln was deposited while November saw a £300mln withdrawn.
Experts said the sharp rise in deposits was clearly influenced by the collapses of banks Credit Suisse, Silicon Valley and Signature – which fuelled fears of contagion globally.
NS&! accounts offer interest rates of around 2%-3%, a better return than gold, another traditional haven in turbulent times, which over the last twelve months has seen a 1.97% rise in value.
Sarah Coles at Hargreaves Lansdown warned: “The level of fundraising the Treasury is currently achieving may, unfortunately, persuade them to slow rate increases in the coming months.”
Commentators have also argued that banks may start to increase interest rates for their customer savings accounts to counter switches to NS&Is and stop a spike in withdrawals.
In total £3.6bln was deposited into bank accounts and NS&I last month, a £300mln rise on January’s numbers.