Telecommunication companies are pushing ahead with the shutdown of the 3G network despite concerns raised during the current Senate Inquiry into it.

The inquiry has warned that threats to public safety were "too great to ignore" and has called for the shutdown to be delayed, calls that telecommunications companies have ignored.

Telstra announced earlier this year it would be shutting down its network on August 31 following an extension to its deadline from June with Optus turning off its 3G network in September. Vodaphone already turned its network off back in January of this year.

During the opening day of the inquiry last month the National Farmers Federation shared its concerns about the 3G shutoff saying that it posed a danger to safety as well as reliability.

Throughout the remainder of the inquiry the Senate was told critical medical equipment, fire alarms, EFTPOS machines and waste and water infrastructure could be cut off in the shutdown. According to industry experts who presented evidence users of cardiac monitors and medical alarms could be unaware their devices rely on 3G until after the network ceases operation.

The Inquiry handed down an interim report recommending the federal government meet urgently with Optus and Telstra to extend their shutdown deadlines to allow for an extensive audit of affected devices.

"The committee believes the dangers to public safety, business continuity and the provision of essential services as a result of the shutdown are too great to ignore and that the shutdown must be delayed until these concerns are sufficiently addressed," the report said.

Minister for Communications Michelle Rowland acknowledged that though the telcos had made significant attempts to reach affected customers there is still more work to be done.

Ms Rowland is encouraging mobile phone users to check the status of their device by texting "3" to the number 3498.

"We strongly encourage all Australians to check their device via the SMS service, respond to messages from your mobile provider and take action," Ms Rowland said.

Optus executive Andrew Sheridan acknowledged the inquiry's recommendations but said the telco was working to mitigate public safety risks by sending text messages to customers and by having provided free and subsidised handsets. The telco has also said it has engaged with businesses that manage devices such as alarms.

"Optus will continue to provide high levels of support to our customers during the 3G switch off through our dedicated teams and keeping device offers open," Mr Sheridan said.

Telstra has said it started informing customers about the shutdown five years ago and the need for customers to be prepared.

"The vast majority of our customers have taken the necessary action to update their devices and we thank them for that. This is reflected by the fact that our 3G network accounts for only one per cent of our total mobile network traffic," a Telstra spokesperson said. "We have a robust communication plan in place through to the closure date and have established processes to help customers after the closure who have yet to migrate."

Both Optus and Telstra have said switching the 3G network off will allow them to provide better coverage for 4G and 5G services including in regional and rural areas and have committed to provide the same as current coverage after the shutdown has occurred.