New figures provided to the ABC reveal complaints about Centrelink services continue to rise.

The figures, recorded by the Commonwealth Ombudsman, show a 24 per cent rise in the number of complaints about the organisation in the last half of 2015.

This follows an even larger increase in the 12 months before that.

There were 3,896 complaints about Centrelink made to the Ombudsman in the six months to January.

That number does not include the department's internal complaints figures for the same period, which are yet to be released.

Before that, in the 12 months to July 2015, the number of complaints to the Ombudsman about Centrelink increased by 26 per cent.

National Welfare Rights Network president Kate Beaumont said more people were seeking their help.

"We're just getting busier and busier," Ms Beaumont said.

"We're also getting lots of complaints about people just not being able to get through to Centrelink."

Government blames outdated IT system

Human Services Minister Stuart Robert confirmed he was aware of the rise in complaints.

Mr Robert said an outdated IT system was a major cause of the problems and an upcoming upgrade would bring relief.

"We're trying to deliver a 21st century offering to a well-educated, technically savvy Australian population — but we're using 1980s IT," he said.

In an effort to fix this issue, the Government will spend $1 billion upgrading that system in the years ahead.

Mr Robert said until that happens he expected complaints to continue.

"With the clunky back end because of the legacy system, I am going to expect to see an uptake in complaints, unfortunately," he said.

Ms Beaumont agreed there were plenty of complaints about connecting to Centrelink online, but she said the problems were much broader than that — and they were getting worse.

"It used to be that something like a claim for Disability Support Pension, people were often told, 'you'll hear in about six weeks' time'. We're having clients now who have got claims that have been in for six months."

'You just feel helpless': Carer

Meredith Ward, who receives a carer payment, has struggled with the agency over a number of years.

Ms Ward works part-time and cares for her two sons — a 20-year-old with autism, and an 18-year-old diagnosed with Asperger's syndrome — who both live at home.

In January 2014, she was told she owed a large debt.

"I received a phone call from somebody from Centrelink just saying, 'you owe us $25,000'. It was an attack on my integrity," Ms Ward said.

It was discovered that Centrelink staff had made a mistake in registering Ms Ward's income four years prior, recording a zero dollar amount, instead of what she had declared.

Having discovered the error, Centrelink investigated Ms Ward — and then confronted her.

"With the first phone call I thought, 'am I up for criminal charges? Am I going to go to jail? What's going to happen?'" she said.

With the help of a free community legal service, Ms Ward won a lengthy appeals process to clear the debt, although more problems have emerged since then.

Ms Ward is fighting a new debt she claims Centrelink has mistakenly recorded against her name.

"You just feel helpless and it drives you crazy, because you think, well, you're trying to do the right thing. I'm not a person who's ripping off the system," she said.

"You're trying to sit on the phone and wait for an hour and a half or two hours to talk to somebody, I mean, it's just overwhelming. You just think, 'I don't have the energy to do that today'."