Australians calling into Centrelink have received 10 million fewer busy signals in recent months, but there are still far more calls going unanswered than there are people getting through.
The number of busy signals recorded between October and March has dropped to 18.1 million, down from 28.7 million during the same period the previous financial year.
The significant drop bucks a long-running trend of increases.
"I'm not declaring 'mission accomplished' yet but we are saying we're seeing a positive trend in the right direction," Human Services officer Renee Leon told a Senate committee on Thursday.
There have been 36.3 million busy signals received by callers to the welfare agency so far this financial year, alongside four million abandoned attempts.
This compares to 23.3 million successful calls to Centrelink.
Ms Leon said the high number of busy signals could well reflect people calling two or three times before getting through, but this was not enough to win over Labor senator Murray Watt.
"Despite all of your efforts, we still have a substantially higher number of busy signals than we do successful calls," Senator Watt said.
"Watch this space, senator, because we are certainly working on bringing down that ratio," Ms Leon replied.
The department credits changes to its telephone systems, extra staff hired through an outsourcing program, and better roster management for its recent improvements on busy signals.
However, while more Centrelink calls are being answered than last year, the average waiting times are higher.
The overall average "speed of answer" stands at 15 minutes and 56 seconds, an increase of 12 seconds on the previous year.
There have also been significant increases in wait times for specific call categories.
Families and parents are waiting an extra five minutes on average, while older Australians are stuck on hold four minutes longer.
Youths and students are also waiting almost four minutes longer, while people calling for employment services are now waiting more than 32 minutes, an annual increase of almost two minutes.
However, call wait times in some other categories have been slashed.
People calling Centrelink about disability, sickness and carers payments are waiting six minutes less, while those calling about workforce participation are getting through two minutes faster.
"These are some of our very vulnerable customers so we have actually improved services in regards to that," Human Services officer Barry Jackson told senators.
Income management call wait times have been reduced from eight minutes and 30 seconds to just three minutes and 24 seconds.
Overall, 97 per cent of calls to Centrelink are being answered in under an hour, and 80 per cent in less than 30 minutes.
There have been 150,000 fewer people stuck on hold for more than an hour so far this year, a drop of 27 per cent.