With less than a week to go until the Census, a phone line designed to cope with requests for hard copies of the forms has been struggling to cope with huge demand.

This year was meant to be the first when the Australian Bureau of Statistics (ABS) survey would be mostly completed online.

But concerns about privacy and whether the network could cope come Census night on August 9 have prompted many households to request hard copies.

The line has been overwhelmed, with callers instead being asked to try again later in the week, or to lodge a request online.

Loading...

Duncan Young, the head of the Census Program, said more people had called up straight away, before receiving the letter with their internet login in the mail, than they had expected.

"Unfortunately we haven't been able to handle the demand, and so we apologise for any inconvenience that people are experiencing," Mr Young said.

"But we want to reassure people that there is still plenty of time, and we will get through all the calls."

He said the number of staff and phone lines was being increased to deal with the large number of callers.

The information-gathering event is held once every five years, and requires participation from every household.

Mr Young said that in the history of Census, nobody has ever been fined for late lodgement.

He also said concerns expressed by some people about their privacy were unwarranted.

On December 18 last year, the ABS announced that at the 2016 Census in August it would, for the first time, retain all the names and addresses it had collected "to enable a richer and dynamic statistical picture of Australia."

Mr Young said Australians had always provided their names and addresses as part of the Census.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 46 seconds 4 m 46 s Listen to the interview with Duncan Young Download 8.8 MB

"It's been the bread and butter of our business to protect that information," he said.

"We can assure Australians that they have legal protections, so it's illegal for us to release identifiable data to anyone, not even courts or tribunals or other government agencies.

"We have the best-practice security protections in place to protect the data."

The Census office has also carried out extensive testing of its technology to see if it can cope with demand.

It said the data required to fill out the Census was small, and should not add too much pressure on internet providers.