The volume of online transactions conducted by National Australia Bank customers will overtake the volume of those conducted in branches by May this year.The bank handles 1.3 million log-ins to nab.com.au each day, with about half originating from mobile devices. Its computer systems manage transactions worth up to A$250 billion each day. And the number of customers who engage with NAB through social networks, such as Twitter or Facebook, grew 400 per cent in 2012. NAB is a third of the way through a 10-year transformation program to install computer platforms able to cope with shifting customer requirements. Last weekend, the bank rolled out the first of four major computer system upgrades planned for 2013, which updated around 200 applications. Adam Bennett, executive general manager of enterprise transformation for NAB, said there were no "major incidents".While the trends point to online banking overtaking physical transactions, Bennett said the bank would continue to invest in both branch and online services, saying the two were complementary.Speaking at the Committee for the Economic Development of Australia in Sydney yesterday, Bennett said that in a short period of time technology had disrupted NAB's traditional business model.The bank's NextGen platform developed and rolled out in association with Oracle is intended to underpin NAB's transformation program and allow the bank to decommission 100 legacy applications.Unlike Commonwealth Bank, which has now completed its core system upgrade, NAB has another six years of transformation ahead of it.Bennett said he was confident NextGen would provide NAB with a competitive edge. However, he also acknowledged that Oracle was actively canvassing the opportunity to install the same banking platform in as many as 100 tier- one banks around the world, meaning the scope of that competitive edge could be limited.But Bennett noted that it was not just other banks which were a competitive threat. "Our biggest challenge is making sure we don't think we have a monopoly on innovation...we have to look outside our sector." He said that he had staff who had, as part of their KPIs or scorecard, an obligation to conduct 12 experiments a year; "Not pilots - experiments - it's a different mindset," he said.In terms of customer facing technology Bennett said; "We are planning for the near future in which electronic payments and digital transactions continue to increase exponentially with customers transacting more often by bumping, waving, tapping or swiping their smartphones."In October NAB partnered with international payments specialist VeriFone to deliver systems that will allow NAB's 130,000 merchant customers to accept payments using tablets or mobile phones. Bennett indicated that the bank would announce its plans for a Near Field Communications solution for contactless payment later this month (March). It first trialled the technology back in 2007.