By midnight on Wednesday, about 840,000 applications had been processed and 250,000 were still on hand, she said.

Meanwhile, almost 12,000 people have been mobilised into Services Australia to help with the coronavirus effort, officials said, revealing the mammoth restructuring among Canberra public servants in recent weeks.

Services Australia is the department that includes Centrelink. New staff from across the public service and from outside are being trained to take calls and process applications, as large numbers of Australians have lost their jobs.

Ms Campbell said the social security offices in Tuggeranong had been reconfigured so staff could work 1.5 metres apart.

Services Australia chief executive Rebecca Skinner said the department had also created an "office in a box", where some staff were given a kit including phone and computer equipment to work from home. New staff and processing staff were largely working from the office, while information technology staff and some more experienced staff were working from home.

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Since March 16, 3414 Services Australia staff had been deployed from other jobs within the department (largely debt recovery which has been put on hold) to coronavirus tasks. Just over 1700 more had been deployed from other parts of the public service to Services Australia. This included staff from an array of departments and agencies, including large departments such as defence, foreign affairs and the Attorney General's department, and smaller agencies such as the Communications and Media Authority, the asbestos agency, and Parliament House.

The department had also employed 6700 people from outside government. Of those, 1546 had been hired as temporary or casual staff, 3125 had been employed through labour-hire firms, and 2103 had been employed via Stellar, Serco and Datacom.

In Tuggeranong, the agency had 1400 people working on the virus response. Another 110 were in Melbourne, 59 in Brisbane, 70 in Sydney and 29 in Adelaide.

The cost of new staff was $28.3 million to date, with other agencies paying the cost of their own redeployed staff but Services Australia still having extra IT and other costs.

Asked about the problems with website crashes and getting help by phone, Ms Skinner said the website had experienced "extreme poor performance early on", given the number of people trying to use it, a problem she compared to the Ticketek website when grand Final tickets went on sale.

But she said performance had been improved. On March 16, the website could sustain 90,000 consistent log-ins at a time. It could now handle almost 300,000 log-ins, she said.

On March 23 and 24 there had been an overwhelming number of people trying to contact the agency by phone, leaving many with conjecture signals, but staff had now been trained to answer basic questions, spending the process, There was an "ongoing challenge" with phone calls for more complicated questions, but people could now apply online without having to verify the application by phone or in person, she said.

Ms Skinner also confirmed some delays in processing claims for child support, the aged pension and youth allowance, but said with the Job Seeker load user control it was refocusing on those claims. Staff taken from the child support area to work on Job Seeker had now gone back to child support. The agency was also processing aged pension claims for people aged over 66 who had lost their jobs and were not eligible for Job Keeper, she said.

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