The £27m technology package was due to be rolled out Scotland-wide last autumn, but there is currently no date for its introduction after issues were identified at the testing stage.
Dr Andrew Buist, deputy chairman of the Scottish General Practitioners Committee, said GPs had been told the new IT would help NHS 24 staff make more accurate decisions about the urgency of patients' conditions and allow them to dispense advice more quickly.
He said: "The length of time it takes to make a decision using computer algorithms is a concern for GPs and we were very much hoping that the promises that were made were going to be fulfilled. The fact there is no date for this starting is disappointing."
However, Dr Buist expressed confidence that NHS 24 would be able to cope with any surge in calls that results from the introduction of a free, easy-to-remember phone number later this month.
John Turner, chief executive of NHS 24, said: "Our guiding principle is the delivery of safe and high-quality care for patients. We currently receive 1.5 million calls each year, which are managed safely and effectively by our skilled and dedicated staff, supported by our technology system."
"Our intention is to continue to develop the system with our suppliers and to deploy it when it is safe to do so."
He stressed the current technology was effective and patients should call NHS 24 when they needed to.