The decision to start daylight saving at the same time in participating states could confuse your mobile phone, Australian Associated Press reports.

Clocks in NSW, Victoria, ACT, Tasmania and South Australia will be wound forward an hour this weekend.

Telstra says the date changes could cause problems for some newer communications devices.

Most phones, PDAs and Blackberries would update the time they displayed automatically, Telstra's executive director of product management, Ross Fielding, said.

"[But] the software on some newer mobile handsets and PDAs may override Telstra's network settings, and change the times to reflect the traditional beginning of daylight saving."

Mr Fielding said mobile phone users should check their device on Sunday to ensure it is displaying the correct time.

If it has not updated correctly, he suggested that users try turning the device off and on, and rechecking it after a few minutes. They could also check whether the "network time update setting" was active. More information was available from the network provider.