The cost of going from a paper to an electronic system in Queensland's public hospitals is costing hundreds of millions of dollars over budget.

The cost of taking Queensland's public hospitals online is expected to blowout by almost $257 million, a probe into the state government's digitising program has found.

Converting paper records to a digital format is intended to speed up the treatment of patients, improve the way medicine is prescribed and allow clinicians to access patient records anywhere and at any time.

The Queensland government wants to digitise 27 hospitals by mid-2020 but analysis by the state's audit office has found the program will run over budget by $256.8 million.

Health Minister Steven Miles says the report, released on Tuesday, is good news and patients are benefiting because of the reforms.

"Doctors and nurses are going about their work in a safer and higher quality way and our hospitals are benefiting," he told reporters on Tuesday.

"It is delivering better results for patients."

Converting hospitals were forecast in 2016 to cost $1.2 billion up until 2025, but the audit office says that has since changed.

"This is mainly because it has recognised that many (hospital and health services) do not have the financial capacity to absorb additional costs," the report said.

"(Queensland Health) is forecasting the total cost will increase by an additional $256.8 million to complete the implementation for all in-scope hospitals -- an increase of 42 per cent."

Digitising the hospitals is being paid in part by hospital and health services but an additional $112.8 million of government funding is needed to finish the job.

Liberal National Party leader Deb Frecklington wants the government to explain why it did not halt the program to resolve technical issues, saying it fast-tracked the work instead.

"This is despite doctors losing confidence, regular system outages and the head of e-Health Queensland being subject to an ongoing CCC investigation for months," she said.

Digitising the state's public hospitals comes after Queensland Health last year took action to prevent hacks on its system, but inadvertently hacked itself in the process.

A payroll system introduced in March 2010 resulted in thousands of staff being overpaid, underpaid or not paid at all in a debacle that costed taxpayers an estimated $1.2 billion.