The Scottish National Party has accused the Scottish Executive of "staggering incompetence" over what it sees as rising call-back times and complaints in NHS 24.

Figures released to the Scottish Parliament in response to a question posed by Stewart Stevenson, MSP for Banff and Buchan, showed that the average callback time rose from under 10 minutes when the service was first rolled out to 49 minutes in May 2005.

Shona Robison, MSP for Dundee East and shadow health minister, said: "While the rise in the number of complaints is worrying, the increase in call-back times is of even greater concern and exposes the executive’s staggering incompetence in managing the service."

Comparing the callback times during the initial roll-out phase of 438,000 with its current nationwide spread of five million, Robison said: "The question is why did the executive continue to roll-out the service and pile more and more work on staff who were obviously already struggling with the volume of calls being received?"

Health minister Andy Kerr said that the targets for non-urgent callbacks were set at one hour for ‘priority one’ calls and two hours for ‘priority two’ calls. Anything considered urgent is dealt with immediately.

Kerr said that progress was already being made in improving callback times under NHS 24’s new leader, George King, vice-chair of Tayside Health Board.

Last month, an interim review of NHS 24 recommended that the service review risks related to callback, such as failure to get back in touch with the patient, as well as criticising a "lack of leadership" and a paucity of knowledge among senior management about pressures on frontline staff.