Bankmaster Plus can be installed more quickly and is cheaper to run than traditional packages, according to Misys.
It uses J2EE and web services and includes modules on investment management, anti-money laundering and investment trusts.
Andrew Derrer, chief executive of Misys Retail Banking, said, "Banks of all sizes have to adapt to a very different market where customers expect more sophisticated products from more channels in more ways.
"The only way banks can succeed is by either cutting costs and competing on price or by out-retailing their competition as well as out-banking them.
"Banks need to have the right architecture to make this move."
A report from analyst firm Datamonitor said the new Misys software offered greater efficiency and lower costs for users.
"From a high-level business perspective the new architecture demonstrates a high degree of alignment with the industry business drivers relating to operational efficiency, flexibility, an integrated customer view, compliance and lower technology costs," said Datamonitor.
According to Datamonitor, the replacement of back-office systems was one of the biggest IT challenges facing banks but that many are unwilling to undertake such a big project.
Other challenges facing banks include having an overview of customer transactions; meeting compliance requirements such as Basel 2 and anti-money laundering regulations; and reducing the money they spend maintaining systems.
Nearly 70% of bank IT expenditure is taken-up by the day-to-day maintenance of IT systems, Datamonitor has estimated.