The research also found that 75% of young adults bank over the internet.
An increasing number of consumers are using their mobile phones for internet banking as banks invest in new solutions to make it quicker and more convenient, new research has revealed.
Figures from the Office of National Statistics found that one in five adults admitted to having made at least one payment via their smartphone this year, while a quarter said they used it to check their bank accounts.
Another 75% of 25-34 year olds and 50% of all UK adults said they use the internet to make payments and check balances.
The research comes just a month after the Payments Council said mobiles would be used to make 1.5 billion transactions per year in 2022, compared with 356 million today.
Clive Adamson, director of supervision at the Financial Conduct Authority (FCA), said: "With the market growing, now is the right time for us to take stock and ensure that consumers are appropriately protected."
Payments Council said that in order to ensure devices are protected, mobile users should only use the official app provided by their bank, install antivirus software and use a password.
A spokesperson from Firstnumber added: "Mobile phone technology is quickly changing the manner in which we pay our bills, monitor our accounts and communicate with our bank. Users should always double check the payment information before sending and always remember to log out of an app or online banking website."
Barclays, HSBC, Lloyds Banking Group, RBS and Santander currently offer apps for Androids and iPhones.