NHS 24 managers have been told to reduce the use of callback

A parliamentary answer revealed it took helpline staff an average of 68 minutes to return less urgent calls in March.

This compared to an average wait of eight minutes when the NHS24 first went live in the north east of Scotland.

The Scottish National Party said the executive should be questioned for continuing to roll out the service.

Figures also showed the number of complaints against the NHS 24 had risen four-fold between 2003-04 and 2004-05. Over the same period the number of calls answered doubled from 615,073 to 1,278,224.

Urgent calls to the medical helpline are dealt with immediately by NHS 24 nurse advisers, while less urgent inquiries are prioritised and processed during peak times by calling the patient back.

Progress is already being made and I expect further progress under NHS 24's new leadership Andy Kerr Health Minister

The target for calling back on less clinically urgent calls is within 60 minutes for "priority one" calls and two hours for "priority two" calls.

SNP health spokeswoman Shona Robison said: "While the rise in the number of complaints is worrying, the increase in callback times is of even greater concern.

"It exposes the executive's staggering incompetence in managing the service.

Service roll-out

"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?"

NHS 24 managers were told last month to reduce their use of callback after an independent inquiry into the service warned that the risks associated had not been adequately assessed and managed.

However Health Minister Andy Kerr said it was unfair to criticise NHS 24 staff, who were working to improve the service following the report last month.

Mr Kerr said: "NHS 24 is here to stay and that's why we commissioned an independent review of its performance to see how it could do better.

"A key objective is to reduce the use of callback, which has been a source of concern, and a number of actions are being taken to address this.

"Progress is already being made and I expect further progress under NHS 24's new leadership."