A glitch in an engine used in the ACT's digital health record resulted in more than 200 missed referrals from clinicians to hospitals.
Some of the referrals were missed for a period of up to 10 months and nine were urgent, meaning the patient needed immediate clinical review.
Officials have moved to reassure the public they have not yet identified any deterioration in patient health due to the error.
The missed referrals were due to an integration engine which has since been replaced.
A brief sent to Health Minister Rachel Stephen-Smith last year, released under freedom of information, said there were 231 referrals missed between November 12 2022 to June 20 2023.
"The health service will follow clinical incident procedures if any deterioration in care is identified due to the delays in receiving referrals within DHR," the brief said.
Of the 231 referrals, 115 had been received through another mechanism before the issue was identified and the remaining 116 had to be resent.
Canberra Health Services say they cannot definitively confirm whether the missed referrals resulted in people waiting longer than recommended for treatment.
"The delay in receiving these referrals varied between patients, and some patients remain on the waitlist. It is therefore not possible to definitively answer this questions," a spokesman said.
Two of the referrals were for a patient who subsequently died, but Ms Stephen-Smith said authorities had confirmed their death was not related to the issue.
"CHS has provided definitive advice on that matter," she said.
The integration engine has been replaced following the issues, it was in use for 436 days but had an expected lifespan of five years.
Overall there were 41,500 referrals through the system. There were 863 referrals that failed but a majority of those, excluding the 231, were picked up relatively quickly.
The 231 missed referrals were only detected following a review of the system and some took up to 10 months to be detected.
Ms Stephen-Smith said the issue was thoroughly investigated and she had not received advice to suggest any patient's health had suffered due to the delay.
"There was a thorough investigation of this matter and a very, very tiny proportion of these were required to be escalated and addressed," she said.
"I have received no further advice that these matters have resulted in poor clinical outcomes."
Shadow health spokeswoman Leanne Castley, who posed the questions to Ms Stephen-Smith, said she hoped a thorough review had taken place to ensure no other patients had been affected.
"The minister needs to be upfront and explain how patient referrals went missing for up to 10 months without anyone knowing," she said.
"It is unfortunate that the minister does not know if patients had to wait longer than clinically recommended due to this failure and hopefully a thorough review has taken place to ensure no other patients are affected."
The digital health record, which went live in 2022, collated all paper and digital records in the territory's public health system under the one electronic system.
It is used daily by health workers to access the health records of patients in the system.
