Smartphones are now considered essential by Australians to the extent that 94% will not leave home without their device, a survey by Deloitte Access Economics and the Australian Mobile Telecommunications Association has found.

The Global Positioning System will roll over this weekend, resetting clocks due to a problem similar to that which caused Y2K, a memo from the US Department of Homeland Security says, with effects expected to be much more severe than when the last rollover took place in 1999.

More than five billion of the world's population are now connected to a mobile network, up from 4.6 billion at the end of 2015, according to a study from the GSM Association released at the United Nations this week.