DETAILED information about electricity customers' power usage, which gives insights into when a house is occupied, is being shared with third parties including mail houses, debt collectors, data processing analysts and government agencies.

Customers with smart meters who sign up for Origin Energy's online portal must consent to their data being shared with a string of third parties. The data is stored in Australia but shared with US company Tendril, which is described by Origin as a smart energy technology provider.

Australia's privacy watchdog said the technology could threaten people's privacy. ''We are starting to see people voicing concern about the level of data that these meters can collect,'' federal Privacy Commissioner Timothy Pilgrim said.

Smart meters were a common concern among Age readers who responded to our series on privacy.