Telcos to proceed with 3G closure despite inquiry fears

Telstra says the overwhelming majority of its customers won't be affected by the closure. (Bianca De Marchi/AAP PHOTOS)

Telstra and Optus have dismissed calls to delay the 3G mobile network shutdown after an inquiry warned threats to public safety were "too great to ignore".

Telstra is due to close the ageing network on August 31, having delayed its June deadline, while Optus will shut down from September.