The $3.8 million cardiac monitors/defibrillators continue to experience problems interfering with the digital transmission of patient information to hospitals.

Paramedics have reported faults with the equipment's Bluetooth connectivity and electrocardiograph information transmission 14 times since last February, when then Emergency Services Minister Simon Corbell assured Canberrans the problems were resolved.

It is understood that one recent case involved a cardiac monitor failing to transmit information of a now-retired ACT Ambulance Service manager, who was being rushed to hospital with chest pain and shortness of breath.

The former ambulance manager has now made a formal complaint about delays to his care.

Shadow Emergency Services Minister Brendan Smyth on Monday called on the government to guarantee the ongoing problems would be fixed.

He said Emergency Services Minister Joy Burch should again go back to the manufacturer, Philips, because the equipment is clearly still not functioning to specification.

"The government years ago told us these were fixed and that there were no problems, and clearly it's not," he said.

There are workarounds that enable paramedics to get the vital patient information to hospitals in the case of equipment failure.

They are instructed to call ahead and talk through the patient's condition, and take a picture of the electrocardiograph information on their phones and send it via multimedia message.

But Mr Smyth said he feared the failures were putting more pressure on ACT paramedics.

"How do they know that these machines are functioning? If this particular function is not working, how can they trust anything else?

"I think it's interesting that the government says it's had no adverse effects, well how can they know?

"The minister clearly needs to tell us as a community when will these problems be fixed and the minister needs to guarantee the community that she will ensure that it is fixed."

A spokeswoman for Ms Burch said the government was committed to providing the "best emergency services possible to Canberrans".

She said no one was put in danger by the 14 transmission issues since February last year.

Time is critical in cardiac cases, and delays can cause further death of heart muscle, hence the common advice "time is muscle".

It is understood the former general manager has alleged his care was delayed by between 30 and 60 minutes.

But the government and the Emergency Services Agency has maintained the problems are not compromising the high quality of care received by patients.

An agency spokesman previously said was not possible to guarantee that transmission of the electrocardiograph information would always be successful.

"Successful transmission of the ECG is reliant on a number of factors one of which includes the availability of a mobile phone network signal for transmission to occur.

"This is not always available in the pre-hospital environment."

The 56 Philips cardiac monitors/defibrillators were purchased to replace models that had reached the end of their useful life.

The faults were still seen on the streets despite months of field testing and demonstrations in staff training.