Customer complaints about Centrelink are up by over 26 per cent in just one year.

The Commonwealth Ombudsman has released its latest review, which pins almost all hope for improvement on a $1 billion computer system upgrade.

But the watchdog is worried that it could be years away.

Ombudsman Colin Neave produced a report on the flood of angry sentiment about Centrelink 12 months ago, but despite efforts to improve since his first review, he says there is a long road ahead.

The Ombudsman said customers were still being pushed onto online systems that are neither “intuitive” nor “reliable”.

He also found that the key performance indicators the department uses to rate itself were not related to the reality experienced by customers.

“If DHS intends to divert people to online service channels it is imperative that the online service works intuitively,” the Ombudsman's report states.

“This is not currently the case with all of DHS's online service channels.

“We understand that the deficiencies may not be satisfactorily addressed until DHS is able to replace its ageing information technology infrastructure over the next several years.”

DHS, which oversees Centrelink, has had a rough week, with reports that its ageing IT system has a glitch that prevents disability pensioners from getting into the workforce.