The bank spent under A$2 million scrubbing up applications for the booming mobile apps market, a tiny fraction of the A$2 billion set aside by it's parent Westpac for the group's IT transformation program.
The Westpac subsidiary wants to carve a niche in the digital space and differentiate itself from other financial institutions.
St George Bank chief information officer Dhiren Kulkarni said smartphone transaction volumes were increasing by 20 per cent a month.
It was one of the first banks to launch an application for the Apple iPhone about a year ago, spending less than A$500,000 on that project and will be the first bank in Australia to unveil a mobile banking application for the touch-based Blackberry Torch 9800. It also has versions for Google's Android platform and Apple's iPad.
Mr Kulkarni estimates the bank has spent less than A$2m developing applications for smartphone and tablet devices.
He said St George customers were embracing smartphones faster than they latched on to the internet - the main reason for the increase was customers were increasingly doing their banking on the go.
"Transactions on the smartphone ... we're doing the equivalent of about 40 branches and increasing by about 20 per cent a month.
"The smartphone is with everybody ... it's mobile, you don't have to log in (like a browser) ... it's convenient."
St George's digital clients used its apps to transfer funds, request credit limit increases and conduct other forms of transactions.
Customers conduct more than 280,000 financial transactions from their mobile devices each month.
No major overhaul of core systems was required to adapt its products to the digital world and the bank's ability to adapt to different platforms seamlessly was due to its real-time processing system, Hogan. The bank has been using Hogan since the 1990s.
"This is where we're pretty smart. We're probably one of the few banks in Australia who's got the online, real-time system (called) Hogan (by CSC).
"This means the backend is the same (for all devices) ... we only change the interface for the iPhone or iPad."
St George worked with a contractor to deliver the free BlackBerry app, which goes live next week on BlackBerry App World.
While some banks like ANZ have decided to primarily focus on the iPhone and iPad, Mr Kulkarni said it couldn't ignore the BlackBerry.
"Most of our big customers have a BlackBerry and they've want this (app)," he said.
St George has around 1 million active internet banking customers and 150,000 active mobile banking customers.