The Department of Human Services, which controls Centrelink, has failed to meet its own targets for processing age and disability support pension claims, with the number of those processed within its target time falling about 20 per cent over the past three years.
Those increasing delays to processing times for the government's two largest social security payment programs have come amid a 5000-strong reduction in staff at the DHS over the past six years.
New data released in answers to Senate Estimates Questions on Notice shows the department failed to meet its own "key performance indicator" targets for the processing of both age pension and disability pension claims, of 80 per cent and 70 per cent within 49 days, respectively, in the September quarter last year.
While processing times for other new claims for pension and support payments had varied - some improved, others steady and still others taking longer - the data released to the Senate shows processing times for new claims for both major support programs have become steadily slower over the past three years.
The figures show the percentage of new age pension claims processed within the 49-day target period fell from 84.3 per cent in the first quarter of 2014-15, down to 61.8 per cent in the first quarter of 2016-17, nearly 20 per cent below the target.
Similarly, the number of new disability support pension claims processed within the target period fell from 84.4 per cent in the first quarter of 2014-15, to 65.7 per cent in the first quarter of 2016-17, some 4.3 per cent below the 70 per cent target.
The increasing delays have coincided with a six-year reduction of about 5000 jobs across the Department of Human Services since 2010-11, including many in Centrelink, which the Community and Public Sector Union believes bears a direct relationship to service delivery.
CPSU deputy national president Lisa Newman said the increasing delays were "exactly what we warned would happen" and that it was "terrible that vulnerable Australians are being caught up in this mess".
It comes amid the controversy surrounding the federal government's debt-recovery program, which Ms Newman said had "made things considerably worse" within the agency.
"It isn't only disability support and aged pensioners who are being hurt by processing delays," she said.
"Last week staff were being offered overtime to help deal with backlogs for Medicare newborn enrolments, new claims for parenting payments and online claims and appointments for Newstart and Youth Allowance.
"Why isn't overtime being offered to help vulnerable disability support and aged pension applicants?"
She said the delays were "the inevitable outcome of slashing 5000 DHS jobs in "just a few years", and there were not enough properly trained staff to deal with existing demand.
Similarly, ACOSS senior policy officer Charmaine Crowe said the social sector was deeply concerned about Centrelink's current capacity to "carry out its core functions" given it had been "failing to meet its own timeframes for processing key payments like the age, disability support pensions and student allowances".
"It's not good enough that people have to wait for more than seven weeks for their claim to be processed and we are worried that some people are experiencing severe financial hardship because of delays," she said.
Ms Crowe said Centrelink was already "under strain" when some 918 jobs were cut from DHS in the last budget and the debt recovery program was further straining the agency's resources.
"Centrelink provides critical assistance to some of our most vulnerable people and government has a duty of care to ensure that it is adequately resourced," she said.
The department did not respond to Fairfax Media questions about the processing delays or any relationship the delays may have had with public service job cuts.