ING Direct Australia's new chief executive, Uday Sareen, has set a goal of doubling the proportion of customers who have a primary relationship with the bank over the next three years.ING Direct has 1.6 million Australian customers and 217,000 of them are primary or "main bank" customers. ING Direct considers a customer a primary customer when they have a transaction account and one other account.Sareen is reasonably confident of hitting that target. About fifteen per cent of retail bank customers switch each year and last financial year ING Direct increased its primary customer numbers by 52 per cent.He said the bank's digital business model was in synch with the way Australians like to bank now.Sareen said: "We have 350,000 interactions with customers each day and 70 per cent of those are coming through mobile. Three years ago we had 150,000 interactions a day."While he is confident the bank can achieve its target, he said there were things it needed to do to get there."We need more products. We are trialling a credit card and we hope to be in the market with that product early next year."We are also looking to launch home and contents insurance product for our home loan customers. That should be in market by the end of the year."Sareen said there was also an opportunity in business lending further down the track. A significant proportion of the bank's customers are business owners.He is also working on some initiatives to increase the competitiveness of the bank's mortgage offering. ING Direct has been growing its mortgage book above system over the past couple of years but he thinks it can do better."We have a competitive rate but what we are looking to improve is the acquisition and processing workflow. It is important to give applicants a decision quickly."By the end of the year we should be able to improve our turnaround times and also give brokers greater transparency about the progress of an application."Sareen took up his post at ING Direct Australia in June. He spent a year before that working on the integration of ING Vysya Bank in India with Kotak Mahindra Bank, which merged in April last year.He started his banking career with Citigroup in 1994 and joined ING Group in 2007 as country head of retail banking at ING Vysya Bank. He spent a couple of years a chief strategy officer at ING-DiBa in Germany.