Some of the most influential political pollsters are ignoring millions of voters because they only call landlines. Even so, analysts are unsure whether that will affect the accuracy of the polling, despite one-in-five Australians being mobile phone-only users.

The number of people who use only mobiles grew by 20 per cent in the past year, to 3.3 million. Most users are city-dwelling renters, aged under 35.

A professor of politics at Macquarie University, Murray Goot, said that, while pollsters had been battling with the problem of changing technology for some time, there was no evidence that the mobile-only surge had affected the accuracy of the election polls.

''Landline response rates are almost certainly declining,'' he said. ''As mobile phone use increases, pollsters will be increasingly concerned that they're getting it right.''

But he said pollsters who did not call mobiles - Nielsen and Newspoll - ensured the spread of ages and gender matched those in the census.