Consumers' use of mobile payment devices is growing fast, according to research released yesterday.PayPal Australia's managing director, Frerk-Malte Feller, said online retail sales to Australians of both imported and domestic goods would grow by 11.7 per cent, to A$30.2 billion, this year and by another 12 per cent next year.Researcher Nielsen said that back in January 12 per cent of active internet users had used a mobile device to pay for an online purchase. Eight months later that number had risen to 30 per cent.Nielsen's research director, Melanie Ingrey, said: "Fifty-eight per cent of those people who had made a mobile payment said they would spend as much or more over the next six months."Feller and Ingrey were speaking at the release of a PayPal report, Changing the Way We Pay. Feller said 15 per cent of active PayPal customers make mobile payments."Two thousand Australian merchants accepted their first mobile payment in the past six months," he said.Ingrey said Nielsen estimates there are 15 million active internet users in Australia. Fifty per cent of these now have access to the internet via a mobile device. Ninety-seven per cent of internet users have purchased online, and 78 per cent of these have done so in the past month.When people choose a payment option they consider security, the price of the service, availability of funds and the speed of the transaction.Of the 30 per cent of people who paid for an online purchase using a mobile device, 26 per cent paid a bill, 14 per cent made a payment to a retail outlet and eight per cent made a charitable donation.